McKinsey Solve Game (2023): How to prepare and ace the Imbellus

The McKinsey Solve Game, formerly known as the McKinsey Problem Solving Game or PSG or Digital Assessment, (colloquially also ‘the Imbellus’) is the consulting firm’s tool to assess candidates in conjunction with the infamous case interviews and personal experience interviews. Let’s have a look at McKinsey’s assessment game.

Introduction of the Imbellus Solve Game

In a series of games developed by Imbellus and psychologists from UCLA Cresst, McKinsey wants you to save the world by building a sustainable eco-system in a reef, a mountain ridge, or in the jungle, and protect a plant species from invaders, before starting your McKinsey career.

The launch and gradual introduction by the world’s most prestigious consulting firm has made quite some waves in the consulting space three years ago, mainly for two reasons. First, the Problem Solving Game is an actual computer game, which is a novel recruiting device in this industry. It replaces the Problem Solving Test (PST), which was a traditional pen-and-paper-based assessment that evaluated how well you can solve business problems under time pressure. Second, McKinsey touts that due to the nature of the games, you cannot prepare for it properly, which left applicants uneasy and confused about how to approach this task. After all, McKinsey applicants are used to preparing for weeks or sometimes even months for their case interviews.

Quick reality check…

It became clear relatively quickly that the latter was more of a marketing statement than anything else. We interviewed some of the first candidates, which took the initial Imbellus Test in London in November 2019, which was the first time that the Solve Game was actually used as a screening device in the recruiting process and not just a beta test. The initial test-taker feedback was very clear.

If they had known what the games would look like and what skills were tested, they could’ve managed it better. Some of them even prepared for the PST beforehand since they were unaware of any changes in the testing strategy. The link to the Solve Game was sent out to them only seven days in advance.

We used their dissatisfaction as a starting point to sit down with experts on the topic while continuing to talk to more and more test-takers from all different countries at the same time. With their input, we were able to develop both strategies on how to prepare but also on how to play the games successfully.

In short: Contrary to the message sent out by McKinsey, you can actually prepare really well for this assessment and develop relevant skill mastery in a short amount of time, mainly by just following the right step-by-step approaches and strategies for each game. Our candidates have proven that with their significant outperformance vs. their peers in this regard.

In the following article, we will highlight the key features and aspects of the Solve Game, which should act as a starting point for your journey to master it.

This article helps you in five areas:

1. We discuss the rationale that motivated McKinsey to switch from the Problem Solving Test to a gamified assessment and what that means for you.
2. We introduce and discuss all 6 games that are currently part (or were formerly part) of the assessment (including some variations that have been reported to us).
3. We brief you on the actual skills that are assessed (beyond what is officially communicated).
4. We discuss preparation methods, exercises, and tools to lift your performance
5. We provide you with insights into proper test-taking strategies to get the best results

If you want to prepare most diligently and make sure that your scores reflect the skills needed to pass the bar, check out our detailed 123-page guide, Excel templates, and 8 videos, in which we discuss every detail of the games, including effective preparation methods and game-winning strategies. You get instant access to the guide, templates, videos, and a free 14-page primer for McKinsey case and PEI interviews. Currently, it contains feedback from more than 450 of our test-takers and several game designers (March 2023).

Be aware that StrategyCase.com was the first to report in detail on this new type of assessment based on genuine first-hand information. This enabled us to collect accurate and constantly expanding insights from our customers.

We released this original program at the end of November 2019 and, since then (after some others just copied and pasted our information), have continuously updated it to reflect the latest changes in the game. To date, more than 7000 applicants from over 60 nations have used the guide to prepare for their Imbellus. 

Currently, we offer a 50% discount. For more details, click here.

McKinsey’s new Problem Solving Game, Solve

“Imagine yourself in a beautiful, serene forest populated by many kinds of wildlife. As you take in the flora and fauna, you learn about an urgent matter demanding your attention: the animals are quickly succumbing to an unknown illness. It’s up to you to figure out what to do—and then act quickly to protect what you can.”

McKinsey & Company

Sounds exciting? Well,…you be the judge.

As a consultant with McKinsey or any other top-tier consulting firm, you often find yourself in situations where you must save the day. On an abstract level, the game simulates exactly this reality. While your consulting career mostly relates to strategy engagements with Fortune 500 companies, McKinsey chooses the environmental scenarios deliberately. More on that in a second.

Traditionally, the McKinsey way of hiring candidates was through the following funnel:

1. Screening: Your consulting resume and cover letter are screened based on a number of filters
2. Problem Solving Test: A 60-minute pen-and-paper test, covering 26 business-related questions
3. Consulting Interview Round 1: 2 to 3 business case and personal experience interviews
4. Consulting Interview Round 2: another 1 to 3 interviews depending on the region (Rounds 1 and 2 can be on the same day in some offices)

With the introduction of the Problem Solving Game (PSG), the Problem Solving Test (PST) was on its way out.

Why would McKinsey get rid of a battle-tested tool, which has been used to screen hundreds of thousands of applicants over the years, and more importantly, replace it with a computer game?

The answer is quite simple and – as ever so often in the McKinsey world – threefold:

1. To attract new talent and new types of consultants.
2. To have an assessment tool that is agnostic (in theory) of people’s backgrounds.
3. To have a lower-cost program (in the long run) to assess a greater amount of candidates.

The Firm is employing the Problem Solving Game to take into account the changes that every consulting firm faces: Changes in its client base, new types of problems the clients face, and its own evolution through organic growth and acquisitions. New problems of clients require a new type of consulting workforce. The typical McKinsey career has changed. Hence, McKinsey is investing heavily in the recruitment of new types of talent, including data scientists, implementation practitioners, IT experts, product and digital designers, as well as software developers in addition to their generalist consulting roles. A digital test is only logical when hiring digital natives.

Above, we teased the environmental abstraction of the game tasks. What is that all about? McKinsey stresses that in order to perform well in the different games, no prior knowledge and preparation is needed or beneficial (contrary to the PST). The natural context should be easily accessible for every possible candidate, regardless of their background. The PST was geared more towards business majors and quant-heavy degrees, evaluating candidates with a simple pen-and-paper test. With the Solve Game, McKinsey has created a much more complex assessment tool to avoid any biases related to a candidate’s culture, experience, or background. Why this is a fallacy and just introduces new types of biases, a bit further down on this page…

Lastly, McKinsey is receiving several hundred thousand applications every year. Can you imagine going through all of them and dedicating proper resources to every single one of them? No? Right, because neither can McKinsey. High-level screening algorithms decide what consulting cover letter and resume gets screened by a human and even then, many candidates are quickly sorted out. As a result, many potentially talented individuals do not make the cut. The Solve Game attacks this issue from two ends. First, administering the Imbellus Game to one additional candidate comes with almost zero additional cost for the Firm. The assessment can be taken from home (in most cases) and does not block many recruitment resources from the local office. It is part of a streamlined and automated process (sounds exactly like what a top-tier management consulting firm would do, eh?). For the PST, on the other hand, candidates had to go to the office to take the test, blocking many resources in the process. Second, with a negligible marginal cost for one additional test-taker, more people can be evaluated and potentially deemed ‘worthy’ of moving on to the interview rounds, even if their resume lacked some important metric that was relevant to the old screening algorithm.

To hit those three points, McKinsey hired Imbellus (which has since been acquired by Roblox) to develop the different games of the Solve Game, a company that claims to reinvent how we measure human potential. A bold claim.

Does the Solve Game live up to this claim and fill its new role as a screening device for applicants?

The role of the new Imbellus test

As a candidate, the Solve Game immerses you in several digital, scenario-based assessments, designed to understand and measure how you approach and solve problems, basically putting you in situations that McKinsey consultants face every day. This approach diverts significantly from other well-known testing formats such as the PST or the BCG Online Case, which test problem-solving skills in a business context.

A digital case interview

The Imbellus replaces the McKinsey Problem Solving Test (which has been discontinued in several offices such as Germany and Austria already years ago due to the bias it introduced – business majors usually got much higher scores).

While the PST is useful when gathering information about a candidate’s problem-solving skills, it introduces a bias toward candidates that are familiar with business problems. Since it favors business major backgrounds, it is not in line with McKinsey looking to expand its hiring base. Also, the PST does not allow for understanding how the candidates arrived at a solution. The Imbellus Assessment allows McKinsey to get both a product score, evaluating how good your solution is, and a process score, providing insights into your problem-solving prowess and approach.

By changing this part of the recruiting process and introducing an abstracted digital assessment, McKinsey hopes to gauge applicants’ cognitive abilities in a bias-free environment, while at the same time collecting way more data points on them.

The game format of Solve

In its current format, the Imbellus has you play 2 games out of a selection of 6 mini-games and lasts between 60 and 81 minutes. 100% of our recently interviewed candidates currently play a variation of the ecosystem creation game, 95% play the plant defense game, and 5% have encountered the red rock study game (the latter has only shown up in Asia and the US so far). Each candidate has to manage their own pace as long as both games are completed once the timer ends. We dive deeper into each game, the different strategies, and time management below.

The scoring of the Solve Game

At its very core, the Imbellus test is still based on standard consulting cases and a consulting interview. You need to identify a problem, collect and analyze data, make a decision under time pressure and without complete information, then formulate recommendations. For that matter, the games evaluate problem-solving skills – but online – using a variety of algorithms.

Initial test data suggest that a candidate’s performance on the Imbellus problem-solving simulation is a good indicator of whether he or she will land an offer after the case interviews. The predictive power is said to be higher than the one of the PST. See below for some hard data on these results.

The McKinsey Solve Game analyzes the skills of candidates in conditions that are closer to real-life situations and that cannot be seen from a consulting cover letter or resume: what approaches do they use to find a solution, how creatively do they approach the task, how do they perceive the world and think. In particular, the test helps to evaluate:

• the ability to correctly identify the problem that needs to be solved
• analyze available information from various sources
• find the right approach to solve the problem, including formulating and testing hypotheses strategically
• draw the right conclusions and make the necessary decision
• quickly react to changes in a situation or its boundary conditions.

Again, in order to measure these traits, McKinsey and Imbellus calculate a

• Product Score: What was the quality of the outcome you reached? Did you manage to ”win” the games by creating a sustainable ecosystem and protecting the plant successfully?
• Process Score: How did you reach that outcome? Every click is recorded in addition to 100+ other variables as you play the games. Were you nervous when clicking around? Did you execute an observable, rational plan?

So how does this affect new candidates?

Current roll-out plan

It’s all fun and games until your score actually determines your future McKinsey career.

One of the most common questions we get from our candidates is if they actually have to take the Solve Game during their McKinsey application. The answer is: likely yes.

The game was initially tested with 5000 candidates in 20 countries between May 2018 and October 2019 in combination with the PST. At this stage, it was not used to evaluate candidates but rather to collect more data, as well as to beta test, and calibrate the games. Additionally, data was also collected from active consultants of the firm who were asked to play trial runs.

Currently, the Firm has fully rolled out the Solve Game globally to most types of applicants, set to assess a greater amount of people with more precise metrics. Our internal customer data shows that McKinsey rolled it out to essentially all countries that host McKinsey offices. The full global roll-out was completed in the recruiting season of 2020 while many key markets were already launched between January and June. 

In 2022 and likely going forward, besides all McKinsey offices using the Solve Game, many candidates nowadays also have to go through the game before being selected for specific recruiting events, such as the McKinsey Women’s Leadership Summit.

Regarding your desired role: The test is mandatory for candidates applying for vacancies in all practices: Generalist consulting roles, Operations and Implementation, Research & Analytics, Digital, and others. Only Orphoz, a McKinsey company focusing on transformations, does not seem to apply the Imbellus games (yet). Additionally, senior and professional hires are often excluded from the requirement to play the game.

Timing of the Imbellus in the recruiting process

If you pass the consulting cover letter and resume screening successfully, you will receive an email with a link to the digitized assessment. You can choose the most convenient time for the test – as long as you do it within 7 calendar days after receiving the link. 

In some offices and geographies, you will be notified earlier (up to one month) about your deadline for the test or get a specific date on which you have to go to the office to take the test, sometimes in combination with the actual case interviews.

In any case, you should start to prepare as soon as possible to learn and internalize the specific skills tested in the Imbellus assessment.

You finished the game: how long do you have to wait for the result?

If you have taken the test from home, the notification of whether you passed the test and move on to the interviews will take between 1 and 14 days (95% of the time) depending on the office and the number of candidates that are currently in the process. The longest we have heard one of our candidates wait for his Imbellus test results was two months (outlier!); on average it is below one week. A couple of offices in Asia recruit on a rolling basis, however, only decide on Solve Game results at certain dates, which could lead to longer waiting times. If you want to expedite the process because you have another offer and need to know, just call HR and they will most likely help you out.

If you have taken the Imbellus together with the first round of interviews, your scores will be evaluated in conjunction with your interview performance (e.g., in Germany). Hence, different offices rely to different degrees on the outcome of the assessment. For some, it is just an additional data point in the first round of interviews, whereas for others it is the gatekeeper to the interviews. Some offices consider the Solve Game result together with your application and application documents. In the latter case, a strong resume or referral might help you balance an average game performance.

How good was my Solve Game performance?

Apart from the official notification, you can estimate your performance quite easily the moment you finish the Solve Game. How? You should know that the ecosystem you have created will survive before submitting your answer and you also know how long it took you to get to a good result. If you took less than 30 minutes to create a sustainable solution, you should have a decent chance. We are using an Excel sheet that can help you check for the survival of your ecosystem. For the plant defense game, you should be able to survive for at least 15 turns in each round, ideally more than 25 or even 30. We discuss what this all means in more detail below.

In general, we expect the pass rate to be on par with or slightly lower than the one of the PST (1/3 of candidates passed the cut-off score of roughly 70% correct answers). The unofficial pass rate that is floating around shows that only around 20% of candidates achieve a successful outcome, which with proper preparation can be lifted well above 80%.

The consulting firm has run beta tests with a significant number of applicants and internal staff to calibrate the Imbellus assessment. Over time, we expect score inflation as people learn more about the test, and preparation efforts increase. Contrary to this, Imbellus is regularly adjusting the games or introducing new games with the goal to avoid predictability and overpreparation.

The skills assessed by the Solve Game

While no business knowledge might be required for the Imbellus, the thinking processes and problem-solving prowess are still the same, whether it’s gamified or pen and paper. In order to maximize your scores in each game, you need to

1. Understand the skills tested and have an in-depth insight into the games
2. Learn proper preparation methods and techniques as well as game-winning strategies

Let’s dig into it.

The 8 core skills Imbellus games assess

The games are all about creating a profile of your skills in several areas. To do this, Imbellus captures and analyses every keystroke and mouse movement. In the end, you will be evaluated based on a product score and a process score. As discussed previously, the game not only evaluates the outcomes you generated but also the cognitive dynamic responsible for how you got there. For instance, it is important for the consulting firm to understand how you made your choices, how you adjust your approach, or when you made errors, how you corrected them.

To score high in the games, you need to optimize both scores and understand the multitude of factors that affect the outcomes you are pursuing in each scenario at hand.

This gamified process tests the following key skills, which are not officially communicated by either McKinsey or Imbellus:

1. Critical thinking: the ability to form a rational judgment from a set of facts
2. Decision making: the ability to select the best course of action among several options
3. Meta-cognition: the ability to use strategies to make learning information and solving problems easier (e.g., testing hypothesis, taking notes)
4. Situational awareness: the ability to determine the relationships between different factors and to project the outcome of a scenario
5. Systems thinking: the ability to understand cause & effect relationships involving several factors and feedback loops (e.g., anticipating several orders of consequence)
6. Cognition: the ability to memorize, process, and store information to then integrate it with existing knowledge and retrieve it when needed
7. Adaptability: the ability to change and adjust your actions and approach to a task in order to suit a new situation or new boundary conditions
8. Creativity: the ability to find creative solutions, approaches, and ideas to different types of problems

All candidates’ actions are tracked by the game and then assessed using data science to score their abilities. The digital assessment gives many more insights into candidates’ skills since McKinsey is able to collect and calibrate the test results of thousands of applicants over time.

The test looks into problem-solving skills, focusing mainly on the ability to work with multifactorial data as well as the candidates’ problem-solving approach. Consequently, it is as important to show how you solve the problem as it is to arrive at a feasible solution.

The Firm then applies people analytics on this fast-growing data set to evaluate, for example, a candidate’s creativity, and the ability to gather information and generate ideas. This approach allows the Firm to observe your thinking, just like in a typical consulting interview, however, in a much more efficient way.

How to demonstrate the most important skills

For instance, the Imbellus tracks your critical thinking skills while you sift through large amounts of data, discard useless information, analyze what matters, relate your findings, and eventually find the best solutions; all in a systematic and orderly pace and manner.

Also, Imbellus analyzes how you make decisions and arrive at conclusions based on the time spent in each menu and different parts of the game, and how you form your recommendation based on this.

The quality of your outcomes strongly depends on your metacognition, essentially referring to what tools you use to process and approach the games. While this cannot be tracked directly, the paths you take through the games provide insights into this dimension.

Situational awareness is another key metric and focuses on how well you are aware of the different elements of the games, the objectives, possibilities, and time constraints.

Systems thinking looks into how well you see interdependencies in the parameters of the games, i.e. matching the characteristics of the food chain with the location in the eco-system game.

Adaptability is especially relevant in the plant defense game with ever-changing map complexities and invader strategies that you need to react to.

Cognition supports you in all this by helping you to memorize information, store, and integrate it with existing data and retrieve it when needed.

Lastly, McKinsey is keen on seeing you come up with creative and novel approaches and solutions to the challenges. Do you deviate from existing candidates, yet, still solve the challenges?

In order to optimize both the product and the process score, you also need to understand what games are part of the deal.

Can you prepare for the Imbellus?

Now to the most important question. Should you actually prepare for the test since the official communication deters candidates from doing so?

Of course, you should.

Our results show that preparation can significantly improve your outcomes (going from a 20% chance to 80%), counterintuitively even more so than for the old PST (as the games are much more predictable than a pen-and-paper test). This is very relevant for the following reason: If you fail the Imbellus game, you receive a 2-year ban to re-apply at McKinsey (1 year for internships). After such a ban, you need to demonstrate significant improvements via your consulting cover letter and resume.

While McKinsey itself argues that you cannot prepare for the games, Imbellus claims that their product measures higher-order thinking skills. Such skills are largely learned through education, training, and experience rather than innate personality traits and inherent cognitive abilities.

Let’s bring in some common sense here: Imbellus did not reinvent the wheel of gaming. The only difference to conventional computer games is that your actions are measured and linked to certain skills. And of course, if you like to play computer games and explore digital worlds, you will fare better in a video game assessment than candidates who have never played such games. In that sense, the Problem Solving Game is just introducing a different kind of bias to the candidate assessment (which can be overcome by applying the right strategies).

So, how can you prepare and elevate your scores for the Imbellus? Let’s first look at the different games.

The scenarios of the McKinsey Solve Game

Timing

The Problem Solving Game usually lasts 60 minutes (for 95% of the candidates we interviewed). However, based on all the input we gathered we have heard from candidates that had 71 minutes or even up to 81 minutes to complete their tasks.

In addition to the timed games, there are untimed tutorials before each game. These tutorials and trials have been expanded to better explain the different games during COVID-19 since every candidate is going through the assessment from home. You can spend as much time as you want on the tutorials. However, once the timed games have been started, they cannot be paused.

The different scenarios

In its original form, the Problem Solving Game includes two individual scenarios revolving around environmental issues, the ecosystem creation, and the plant defense game.

Starting in August 2020, we received some feedback about changes in the games. Some candidates got the ecosystem creation with a variation of the original game AND the disease identification game instead of the plant defense. In these cases, however, it was communicated that the disease identification was not used to score candidates but rather for future use and calibration in the Imbellus test. Another game was introduced in 2021, migration planning, however, as it appears by the end of 2022, it has already been discontinued.

Be aware that new games and game variations can and will pop up in the future. Over the last three years, we have seen six games in total. However, since the consulting firm wants to make sure that results and the skills evaluation remain consistent over time – just as they do with their consulting interviews – they would not just introduce new scenarios to evaluate candidates right away. Rather, they would introduce variations of existing games OR introduce new scenarios for beta testing purposes, meaning that the latter will not be used to make decisions about a candidate but rather to correlate performance across scenarios and calibrate results and difficulty levels. Out of the six games we saw over the last three years, the ecosystem game and the plant defense game are still dominant. The only other game that you have to currently expect is the red rock study game (with a chance of around 5% to actually play it).

Watch this space as we are regularly updating our article and our guide to reflect changes in the Solve Game.

Let us briefly look at each Imbellus game example.

In the standard version of the game, you will encounter two distinct worlds, which are visually depicted and task you with different challenges:

Ecosystem creation

The first challenge candidates encounter is usually placed on a scenic mountain ridge, in a coral reef, or in the jungle. The game gives you two objectives with the overarching goal to create a sustainable ecosystem. For this, you need to, first, select eight species (plants and animals) for a food chain and, second, match the food chain with a suitable location on the map.

In this scenario, regardless of the time, you are allocated (McKinsey recommends 35 minutes, prepared candidates need less than 25), your task is to create a sustainable and lasting ecosystem on a mountain ridge, in a coral reef, or in the jungle, based on the complex system and associated interactions of the food chain and the location itself. At the core, the game is an optimization problem. You will be confronted with an overload of different data points (similar to the McKinsey Problem Solving Test, yet not business-related). You match the location to the species as well as the species with each other based on many different characteristics such as calorie need or provision and environmental requirements such as temperature, sun exposure, etc. All requirements need to be fulfilled at the same time to create and sustainable ecosystem and to successfully pass this game.

There are 2 parts:

First, you need to pick 8 species, either animal or plant, to inhabit the mountain, reef, or jungle location. Selecting a suitable, heterogeneous sample for the food chain relationship out of the numerous species is crucial. You need to account for the interaction effects between the species (e.g., coral, aquatic animals, algae, etc. in the reef) and several individual characteristics such as the required environment, place in the food chain, how many calories they need to survive, or how much energy they need, how many calories or energy they provide when consumed, etc.

Second, you need to decide on the location of the ecosystem to create good living conditions for several species. You need to consider several characteristics of the location such as altitude, cloud height, ph-level of the soil, wind speeds, precipitation, etc. for the mountain ridge or depth, temperature, salinity, etc. for the coral reef.

The catch in this game is that you are presented with information overload and need to show proper systems thinking. The food chain must not collapse, and the ecosystem must sustain itself. You will know if you have provided a good answer before submitting it since you can test your hypotheses to see if the ecosystem could actually sustain itself.

In the summer of 2020, McKinsey started to introduce new boundary conditions to make the game more challenging. For instance, you not only need to create the food chain with several levels and match it with a location but also adhere to certain new rules related to the hierarchy of the food chain. This twist adds another dimension you need to consider when drafting your solution. Roughly 5% of the people, we talked to, encountered this particular variation of the game back in 2020. By June 2021, all candidates reported these more elaborate eating rules as part of their assessment and they have been in place ever since.

There are several ways how to approach this scenario, which we worked on with our candidates and created an Excel sheet that helps you solve the eco-system puzzle. Below is a high-level approach you can use when going into the game. The first 4 steps focus on the food chain, and the last step is on the location selection:

1. Figure out the dominant location requirements of your species selection.
2. Eliminate all species that do not fall into the dominant location set.
3. Build your food chain bottom-up or top-down.
4. Sanity check if all animals can survive (following the calculations and the eating rules).
5. Identify a suitable location.

Most importantly, have a plan ready before you start:

1. Do you want to pick the location first or the food chain?

2. Do you want to build the food chain top-down or bottom-up?

There is no single right way to do it. Choose what works best for you and stick with it throughout the game. We discuss each strategy with a step-by-step approach as well as provide you with an Excel sheet that helps you check the sustainability of your ecosystem in our McKinsey Solve Game Guide.

Plant defense

In the second scenario, you need to defend a plant species from invaders using several tools at your disposal in a static, round-based tower defense-style game. The tools consist of barriers that slow down invaders and predators that damage and eradicate them.

In this scenario, which, for the majority of candidates, is a bit more challenging than the first, you need to defend a plant at the center of a map from an invasive species for as long as possible. This scenario is broken down into 3 rounds. Each round lasts between 8 to 12 minutes, presenting a slight variation of the game with increasing complexity and an increase in the map size. For each round, invaders spawn in several turns per map.

Each round is divided into two parts.

In the first part, you can actively manage your defense strategy in order to react to new invaders that spawn every 3 to 5 turns. You can manage 15 turns by initially placing your defense units on the map, adjusting their positioning after every turn, and selecting new defense units every 5 turns.

Your goal is to have the plants survive each of these increasingly difficult turns. You can slow the invaders down so that they do not arrive at your plant within the number of turns or eliminate them fully before they would do so.

In the second part, the endgame, you are no longer able to change your strategy and the placement of your defense units. The game fast-forwards until your plant is defeated. Depending on the quality of your last placement strategy it might take the invaders many turns to kill the plant, ideally more than 30.

Your goal is to optimize for the plant to survive as many turns as possible. Your product score is the direct result of the turns survived, while your process score focuses on how well you adjust to changing behaviors of attackers and how much you can learn and adapt over the course of the turns and over the course of the 3 rounds.

In order to do this, you need to choose certain animals that eat the invasive species and natural barriers/ terrain to slow them down and block them, in a static and turn-based environment, contrary to most other tower defense games that are dynamic.

You are presented with information about what each tool such as animals or geographical/terrain barriers can do, e.g., how many invasive species an animal can kill in a given time or how much a forest can slow the invaders down. These animals have different stats in terms of their reach/sphere of influence (shown as squares) as well as the damage that they are able to inflict on the invaders.

For instance, there could be a dog and an eagle as animals. The eagle has a large radius and inflicts less damage whereas the dog has high damage but a smaller range of effectiveness (e.g., one square only). Some animals have a large radius and high damage (usually during the last game). The damage inflicted might also differ depending on the type of invader. The barriers are elements such as mountains, rocks, and forests. Mountains block invaders and make them change their pathway toward the plant (ideally make the pathway longer). Rocks, and forests slow invaders down (different effectiveness for different invaders)

The invaders will start attacking the plants once they reach it in the middle and the game ends.

While initially, you will be able to kill the invaders, they will show up in greater numbers in each consecutive wave and it is possible that you will be defeated. This is not, per se, a bad thing since it will die eventually in the fast-forward mode of the game. Keep the plant alive for as long as possible.

The aim is to defend the plant in the center for as long as possible, hence, to kill all invaders before they reach the plant. It is very important to make use of both defending animals and barriers to unlock their synergistic effects and keep the invaders as long as possible in the sphere of influence of the animals.

Use the untimed tutorial to think about the most effective combinations and layouts of the tools before starting the game. Prepare using video games in the tower defense niche to train yourself for this scenario. The key in this game is to show adaptability by being able to learn quickly, and improve your strategies and reactions with each turn and with each game.

Creating a strategy

Let’s again break down your approach into several steps.

1. Familiarize yourself with the map
2. Create your initial strategy
3. Focus on new invaders first
4. Secure the plant from future attacks
5. Adjust your strategy as the game evolves

We discuss each step, variations, and successful start-to-finish strategies in full in our McKinsey Solve Game Guide, which has been co-created with the help of tower defense game designers, who developed games for iOS and Android.

Red Rock study simulation

The current 3^rd wheel in the Solve Game lineup is the Red Rock Study game. A small minority of candidates (around 5%) have reported having taken this task since summer instead of the plant defense game. With this game, McKinsey is moving back into a more typical business-like analysis and problem-solving situation. The look and feel are very similar to older BCG Online Cases. The only difference is that you are not a consultant but a researcher (according to the definition of the game), yet the tasks you focus on mimic what a typical consultant would do. The game evaluates skills such as information processing, data collection, case math (e.g., calculating averages or percentages), exhibit interpretation

In your role as a researcher around certain scenarios, you have 25 minutes to move through a three-step process.

• First, in the Investigation stage, you are shown an objective for your research and data in the form of text, tables, and charts. In this stage, your goal is to gather insightful and relevant data and store it in your research journal on the screen.
• Second, once you move to the Analysis stage you have to answer three math questions related to the research objective. You can use an on-screen calculator to facilitate calculations, however, the challenge is to come up with the right approach and filter for the right data. You can move between the Investigation and Analysis stages (e.g., if you are missing some information).
• In the third stage, the Report part, you need to summarize your findings and visualize your supporting data with a suitable chart.

Creating a strategy

We have created a 4-step strategy to tackle this game.

1. Figure out what you need to do by reading and interpreting the objective of the game (Investigation Stage)
2. Prioritize the relevant and insightful data (Investigation Stage)
3. Set up and perform your analysis and calculations (Analysis Stage)
4. Visualize the data (Report Stage)

The skills that are needed in this game are much closer to an actual case interview and we would recommend that you take a look at our articles on

• Case Interview Math
• Case Interview Exhibit Interpretation

Be aware that the game is still in its infancy and we have seen many iterative changes to new games in the past. As a result, be prepared to encounter minor variations or adaptations when you face the Red Rock simulation.

Update to the Red Rock Study Game

In March 2023, McKinsey introduced a new component to its Red Rock Study assessment – a mini case featuring 10 quantitative reasoning questions related to the study segment’s context. This addition has intensified the challenge, as candidates now have only 25 minutes to complete both the study part and the 10 case questions. Previously, the 25-minute time limit applied solely to the study segment. Consequently, test-takers must think quickly and manage their time efficiently to complete the entire assessment, which has proven difficult for many candidates that we interviewed. Update (late March 2023): Some of our customers now reported that they had 35 minutes for both parts with the recommendation to split the time equally.

The mini case’s 10 quantitative reasoning questions require strong quantitative and analytical skills, as test-takers must swiftly and accurately interpret information from various charts and textual sources to perform calculations and derive correct answers. This shift not only departs from McKinsey’s prior game-based assessment approach but also brings the Red Rock Study assessment more in line with the evaluations utilized by other consulting firms.

We cover this game and the up-to-date changes in more detail in our McKinsey Solve Game Guide.

Disease identification

It seems that McKinsey reintroduced a game that was already present in the beta testing stages of the PSG, with a slight variation. It replaced the tower defense game for roughly 5% of the candidates over the course of late 2020 and early 2021. By June 2021, it appears that the game never really made it out of the testing stage and we have not heard about any reappearance in 2022. Nonetheless, let’s look into them since we cannot guarantee that they won’t come back in one form or another.

As a player, you are tasked with identifying which animals on the map will be infected by a given disease. The nature of the disease is not important. What is important is to identify patterns of the disease and ultimately identify which animals would be infected in the next turn.

The game has many animals on the map. There are also three time periods, which they call Time 1, Time 2, and Time 3. In Time 1, a small subset of animals is already infected. When you click on Time 2, that same map will show which additional animals got infected. Your goal is to identify which animals will get infected in Time 3. The approach to this game is relatively simple:

1. Figure out what the key variables are that could give a hint about the disease progression.
2. Create an array of different filters and look at them through different points in time to see the changes in the animal population.
3. Move to time 3 and select the next animals that will be affected by the disease based on your tested hypotheses from step 2 (e.g., if you know that all animals above 6 years are affected by the disease and in time 3 there are 20 new animals that are above 6 years of age, select them)

Contrary to the old version which was used in beta tests before the game was actually launched, you do not need to provide a remedy or a treatment plan. We discuss this game including a video briefing in greater detail in our PSG Guide.

Disaster identification

Another game that has not made a new appearance in 2022. In this game, candidates had to figure out the nature of a natural disaster impacting an animal population and then place the animals on another area of the map so that the most number of animals survive. The mechanics are similar to the ecosystem game.

In this game, you can display three things, a map, species, and a list of events. You can tackle the game in 4 steps:

• Identify what event has happened in an area (a natural disaster such as a tornado or a flood) by combining information from an event description with variables on the screen.
• Identify dominant ranges to move the animals to an area that is best suited for their survival.
• Select the location by clicking on it and check for the relevant ranges you identified before. Prioritize characteristics that allow for the greatest number of animals to survive.
• Sanity check your selection in a similar manner as for the ecosystem game.

Migration planning

A new game that appears to have arrived in the Imbellus Game is what we call migration planning.

Your task is to plan the migration of 30 to 50 animals from a starting position to an endpoint on a map by selecting the best route out of several alternatives.

You have to solve up to 15 different scenarios within 35 to 40 minutes. Each scenario consists of 3 to 5 turns that have you decide on the next step of your route. In turn 1 you select the first step on your route, in turn, 2, the second leg, and so on until you reach the desired endpoint.

You start with a given number of animals and a specific set of resources (consumables such as food or water). With each turn of the game, a predetermined number of animals will die, and resources will be reduced by a specific amount, depending on your selected route. Alternatively, you can also select intermediate points on your route that will replenish and multiply existing resources as well as collect additional animals along the way.

The objective of the game is two-fold: First, you need to ensure that the highest number of animals survive until you reach the destination. Second, you need to arrive at the endpoint with some of the resources preserved as well. As said before, there are up to 15 different scenarios with 3 to 5 turns each, which leads to 45 to 75 unique decisions you must make along the way.

We provide you with a specific table and approach that you can use to create your strategy for each route in our McKinsey Solve Game Guide.

Prepare for the McKinsey Solve Game

McKinsey tells candidates that preparation is not needed and not possible. However, the feedback we have collected from more than 450 candidates point to the fact that you can actually prepare really well for the different scenarios.

For that matter, we have analyzed the test, talked to game design experts and test-takers, and turned to science-backed methods to create a very detailed guide for the game and its mechanics.

Below are some higher-level pointers you can use as the foundation of your preparation.

Imbellus game practice

Train the key skills that are being assessed by Imbellus. Playing logic games, mobile games, and tower defense games with similar themes can be beneficial to train these areas specifically. While these games will differ somewhat in their user interface, objectives, and mechanics they still train your skills, make you think about potential strategies, and just get you in the habit of interacting with a gamified environment. If you have sufficient time before taking the Imbellus, try out some of the games below to practice the Imbellus gameplay.

Games for the ecosystem and migration planning

• Plague Inc. – if you have limited time, focus on this game
• Sim City
• Cities: Skylines

Games for the plant defense

• Tower Duel – if you have limited time, focus on this game
• Kingdom Rush
• Plants vs. Zombies

Figure out what your weaknesses are and tailor your preparation with specific problems to solve. Additionally, this preparation will benefit your case interview skills. McKinsey Solve Game practice could very well make the difference between your success or failure.

General preparation advice

In addition to playing games that are similar to the Imbellus, there are a few other things that you need to do to improve your performance on the relevant metrics.

• Develop and internalize a plan on how to approach every decision. Use a step-by-step decision-making process to help you make more deliberate and thoughtful decisions. This approach increases the chances that you will choose the most satisfying alternative possible by organizing relevant information in all games. Learn the steps below before attending the Imbellus, as these steps are crucial for each of the 6 games.

1. Identify the decision. Clearly define the nature of the decision you must make. What is the real goal that you need to achieve and what side quests does it entail?
2. Gather relevant information. Collect some pertinent information before you make your decision: what information is needed, what are the best sources of information, and how do you get it.
3. Identify the alternatives. As you collect information, you will identify several possible paths of action or alternatives.
4. Weigh the evidence. Draw on your information to imagine what it would be like if you carried out each of the alternatives to the end.
5. Choose among alternatives. Once you have weighed all the evidence, select the alternative that seems to be the best one.
6. Review your decision and its consequences. Consider the results of your decision and evaluate whether or not it has resolved the need you identified in step 1.

• Just as for the actual case interview, learn how to take proper notes. Write down your observations on the mechanics of each scenario. Prepare Excel templates that can guide you during your assessment. It will help you structure your thoughts and reach a solution quicker. As Imbellus states, so far, the notes have been collected after the test. However, it is unlikely that they will be taken into consideration for the screening decision. The game itself provides more than enough data points to automatically analyze a candidate. This is only relevant if McKinsey were to decide to conduct the Imbellus in an office setting again.
• Learn how to structure problems. Learn to structure, analyze and synthesize complex problems to help you develop recommendations by combining logical thinking and creativity. When asked a question, take some time to structure your analysis (similar to when you are structuring your approach in a case interview). Consider what topics you want to look into, what information is needed, and how you can get this information, all with the goal to gain key insights in the shortest possible time to come up with excellent analysis. The goal is to derive creative and sustainable recommendations that are effective.
• Learn how to tackle problems with a hypothesis-driven mindset. Use a hypothesis-driven approach to guide your thinking and problem-solving to reach sound recommendations or actions. In order to direct your analysis, give it a clear focus, and help you to find the problems and derive recommendations quickly, train to come up with one or more hypotheses at the start of each game, then test and refine the hypotheses as you move along.
• Learn how to visualize processes and relationships. One of our favorite habits we recommend in consulting interviews is to apply a process-based view of the problem at hand. Before tackling the Problem Solving Game, you should internalize ways of creating quick sketches to visualize situations, processes, relationships, and patterns. Mapping out a process can be useful in several scenarios, especially when you are not familiar with a certain task or system of interactions. When laying out what constitutes a certain issue, you will be able to understand it by breaking it down into its constituent parts.
• Get comfortable with estimations and simple math. Simple and quick math is needed for all games since you need to calculate the different calorie budgets in the ecosystem game, the multiple damage points of your attackers in the tower defense game, as well as the optimum route in the migration planning game. That way you will be able to calculate and compare the expected outcomes of several options. After all, that is the same skill that was already needed for the McKinsey PST and is still needed for the consulting case interviews that follow the digital assessment.

Apply the right strategies for every game

Strategies for every game

Each game of the Imbellus requires a different approach and mindset. We have summarized each strategy in the infographic below on a higher level. For step-by-step instructions on winning strategies, check out our McKinsey Solve Game Guide.

Ecosystem creation

Build a food chain pyramid by selecting 8 species (animals and plants).

• Optimize for caloric supply and intake
• Build top-down from the main predator
• Adhere to randomly generated boundary conditions and eating rules

Select the location where all species can survive.

• Look for the key influencing variables
• Match across food chain and location

Plant defense

Protect a plant on the map from invading species by placing a combination of animals and barriers to

• slow down
• decimate the

attackers and prevent them from reaching and attacking your plant. Make sure that the plant survives for as many turns as possible.

Red Rock study

• Use the research stage to sift through information about your objective and the data that surrounds it
• Save the most relevant data points and write down important bits on paper
• In the analysis stage, answer questions, going back to your notes and using the in-game calculator
• In the report stage, visualize results with the visual tools’ interface

Disease identification

Identify a subset of an animal population that is affected by a disease

• Identify patterns of how the disease spreads based on certain characteristics in the animals
• Predict what subset of the population will be affected next by extrapolating the progress of the disease

Disaster identification

Identify a disaster based on certain variables and move animals to a new location that fits them best (similar to ecosystem creation)

Migration planning

Organize the migration of 30 to 50 animals from one spot to the next by managing resources and animals from start to finish in 3 to 5 turns. Select the most optimal route to preserve resources and animals along the way and pass 15 rounds in total.

Map the routes on a piece of paper or in an Excel sheet.

• Write down each available route
• Calculate the outcome variables for resources and animals for every route
• Select the route where most animals survive and resource requirements are met

Strategies to adhere to for all games

Additionally, we have compiled some tips to get you started on your way to mastering the games. Internalizing them will also help you during your consulting interviews in general:

• Do not try to replicate results or solutions since every test taker will face a uniquely generated scenario in the Imbellus recruiting game. All games are set in an ecological context to be accessible to all backgrounds. At the same time, no two test-takers will have the same experience as there are tens of thousands of possible variations of the same game, all with the same level of difficulty. Artificial intelligence should ensure that the virtual environments and animals look indistinguishable from reality to put candidates in a flow state and full immersion when playing the game. Focus on the process instead and replicate strategies (which we have devised in our guide)

• Get ready to make 80/20 decisions based on incomplete information. Likely you won’t reach the best answer within the given amount of time, however, you should reach a good answer, demonstrating a clever problem-solving strategy along the way. Be careful not to get bogged down by the details and lose yourself in the several subcategories the game provides. Similarly, test your ideas and write down the different outcomes

• Read the instructions carefully. With an increasing number of variations in the games, some candidates have reported to us that they initially did not see a particular instruction, making their solution for the ecosystem scenario invalid. Make sure that you understand clearly what your task is

• Make sure your setup works if you are taking the test from home: before starting the test, the system will automatically check the internet connection. Still, make sure that your computer is charged, the internet works, and your system is stable since the test cannot be repeated or paused when it crashes. Candidates with older computers and laptops reported that their CPU usage was maxed out and the fans were going on full steam. Make sure that this all checks out before and borrow a laptop from a friend if you think your system can’t handle it! If an issue presents itself during the test, you can always talk directly to the 24/7 Imbellus service center

• As with the Problem Solving Test – Keep an eye on the time! It is easy to get lost in the details and the sheer complexity of the information overload the test presents. However, make sure to go swiftly through the tutorial, keep track of the time, and roughly stick to the 30 minutes for each scenario. The progress bar on top shows the remaining time.

Now, we have a lot more to offer with regard to proper preparation methods, and test-taking strategies. Check out why you would benefit from our Guide below.

How our guide boosts your score

If you want to improve your score and increase your chances to pass the test, check out our 123-page guide (including Excel templates, and 8 videos on the interface and the gameplay strategies of all games + a free McKinsey interview primer) with a detailed look at each scenario, proven methods on how to prepare for the Imbellus game, as well as examples, tips, and strategies to win the games. You get instant access to the PDFs, the Excel templates, and the videos. Our guide is the gold standard in McKinsey Imbellus Solve Game preparation for a few reasons:

Benefit from our experience since the inception of the game

1. We were the first and the only ones to offer a guide based on genuine, first-hand information. We started out by interviewing trial test-takers, game design, and assessment experts in November 2019.
2. We continuously interview our customers and now have a database of more than 450 first-hand experience reports and feedback.
3. Their feedback has helped us to reach more than 7000 test-takers in more than 60 countries and continuously improve the guide and adjust it to the latest changes McKinsey is introducing. We usually update our guide once a month or whenever our candidates report significant changes. Once you buy the guide, you will receive future updates before your testing date.
4. As former McKinsey consultants and consulting interviewers, who left the firm recently, we have a deep understanding of how McKinsey thinks and evaluates candidates. Benefit from our specific insights you will not find on generic case websites with coaches that never worked in consulting or did a 6-month stint in a different firm several years ago.
5. We go into more detail about the interface and the gameplay strategies in a 8-part video commentary for all games in addition to the written guide and the Excel templates. It is much easier to discuss the McKinsey Imbellus game secrets on actual screenshots in video format.

Battle-tested approach for high scores

Our preparation strategy is based on 5 pillars:

1. We help you understand what McKinsey is looking for in their new-generation consulting force
2. We teach you in great detail how the scenarios and different games look like (user interface, gameplay mechanics) as well as what you need to do (objectives, core problems)
3. We discuss the 8 core skills that are assessed by McKinsey and how you can train them with actionable advice, methods, tools, exercises, and links to external resources
4. We provide you with test-taking strategies and actual tools that work! Learn how to really approach the ecosystem game, the plant defense, the red rock study, the disease identification game, the disaster identification, and the migration planning task (March 2023) in written and on video. We collected them through our interviews by correlating candidate approaches with their successful outcomes. Over time, the outperformance of our candidates that applied our McKinsey Imbellus game secrets over their peers has steadily increased.
5. We show you the right hacks to fast-track your preparation and get ready for the Imbellus in no time.

Additionally, you get access to our McKinsey applicants’ inner circle where we will provide answers to all your consulting interview questions within 24 hours.

Also check out our other products and services, specifically tailored to rocking your McKinsey interviews.

Our McKinsey Solve Game Guide

The original and most comprehensive guide from former McKinsey consultants with

87% pass rate in the Solve Game*

Your benefit

• Crack each of the 6 games with our proprietary guide and video insights on the exact steps
• Score high with tailored strategies and gameplay walkthroughs based on successful test-taker feedback
• Focus on what matters most and don’t waste time in your preparation with proven ways to master all skills
• Prepare with 100% confidence for the latest changes in the scenarios with our constant update policy and free lifetime access guarantee
• *based on customer feedback from Jan – Feb ’23

Our Credentials

• Helped 7000+ students from more than 60 countries since November 2019
• Based on 450+ test-taker interviews since the inception of the game, expert game designer input, and our McKinsey experience
• Includes a 123-page guide, Excel templates with formulas, and 8 videos on the gameplay and winning strategies + A FREE 14-PAGE MCKINSEY INTERVIEW GUIDE FOR CASE AND PEI
• 100% proprietary content – often copied, never equaled

McKinsey Solve Game Guide (Imbellus) 16th Edition (incl. videos and Excel templates)

SALE: EUR 69 / EUR 34

If you have taken the Imbellus game and want to share your experience and Imbellus game tips or have further questions, please let us know in the comment section below!