Secrets of Game Engagement

1. Mastery Engines

In the first of our deep-dive articles analysing game engagement systems, we explore those titles that invite players to perfect their tactics and sharpen their performance.

Balatro Roguelike Deckbuilders Explained Resident Evil 4 Mastery Through Constraint Vermintide 2 Mastery Under Pressure Why Mastery Engines Engage Players

Across our Steam dataset, one pattern appears with particular clarity: certain games sustain engagement by encouraging continual skill improvement. For these titles, players return not because there is more to see, but because there is more to learn.

Unlike progression-driven games, where engagement is tied to unlocking new content, mastery engines derive their staying power from optimisation. The player’s objective is not simply to advance, but to perform better next time around. 

Crucially, the experience is not exhausted after completion. Instead, each session reveals inefficiencies, missed opportunities, or alternative strategies. The result is a simple but powerful loop:

decision → outcome → feedback → adjustment → retry

This is the core of what we describe as a mastery engine.

Three games in the dataset illustrate this dynamic particularly clearly: Balatro, Resident Evil 4, and Vermintide 2. Each one presents a different form of the mastery engine, but all sustain engagement through the same underlying principle.

Balatro

Among these, Balatro is the clearest expression of the form.

At a surface level, this roguelike deckbuilder resembles a familiar card game. Players draw from a deck, create hands, and optimise outcomes based on probability. In that sense, it overlaps with traditional games such as poker or rummy, and the moment-to-moment decisions feel recognisable. But this similarity is misleading; the player is not just playing within a system, they are actually reshaping it. 

In a conventional card game, the rules are fixed. The deck is fixed. The scoring system is fixed. Improvement comes from making better decisions within a stable structure.

Balatro breaks this assumption. Over the course of a run, the player modifies the system itself. Cards are added or removed. Scoring rules are altered. Jokers introduce effects that reshape scoring rules, for example, multiplying specific hand types, rewarding unusual combinations, or turning normally weak plays into high-value strategies.

What is a roguelike deckbuilder?

The term 'roguelike' originates from Rogue, a 1980 dungeon-crawler that established a set of systems that now underpin many modern games. In roguelikes, each playthrough begins from scratch, with environments, items, and challenges generated differently each time. Progress is not carried forward, and failure resets the run entirely.

A deckbuilder, by contrast, is built around modifying a set of cards over time. Rather than playing with a fixed deck, the player gradually adds, removes, and transforms cards, shaping how the system behaves.

A 'roguelike deckbuilder' combines these ideas. Each run begins with a basic deck and evolves through a series of choices, often influenced by randomness. The player is not only making decisions within the system, but altering the system itself as the run progresses.

A strong build might invert the logic of the game entirely. Hands that would normally be weak become dominant. Actions that appear inefficient, such as discarding cards, become central to scoring. The player is no longer optimising within a system, but constructing one.

This creates a distinct form of tension. Almost every decision carries an element of risk. Players are constantly weighing short-term gains against longer-term potential, whether to commit to a strategy, reroll for something better, or push for a higher-scoring outcome. In this sense, the game reproduces many of the emotional beats of gambling - uncertainty, near-misses, sudden payoffs - without any external stakes. The reward is not money, but the satisfaction of seeing a system come together.

Mastery as System Construction

Each run begins under conditions of uncertainty. The available tools are partially random, and their interactions are not fully predictable in advance. The player must adapt, experiment, and refine their approach in real time. Failure resets progress, but carries forward understanding.

Over time, this creates a shift in perspective. Early runs are reactive, driven by immediate possibilities. Later runs become deliberate. Players begin to plan several steps ahead, shaping their deck and modifiers towards a specific outcome. Runs are no longer reactive sequences of hands, but controlled attempts to execute a strategy under changing conditions.

Crucially, outcomes remain legible. When a run fails, the reason is usually clear, for example playing a Glass Joker too early, or forgetting to use vouchers such as free rerolls. The system provides enough clarity for the player to diagnose error, but enough variation to prevent complete mastery.

In this sense, Balatro is not simply a game of cards. It is a game about constructing a system that determines the function of those cards. The player returns, not to see something new, but to design a better system.

This balance is what sustains engagement. Randomness ensures that no two runs are identical. System modification ensures that each run evolves differently. But it is the player’s growing understanding that determines how far they progress. Over time, players begin to pursue increasingly powerful “broken builds”, highly optimised combinations producing extreme scoring outcomes that are shared within the player community.

In this sense, Balatro is not simply a game of cards. It is a game about constructing a machine that determines the function of those cards. The player returns not to see something new, but to construct a more effective system, one that turns uncertainty into advantage.

A Mastery Engine Par Excellence

Balatro exemplifies the mastery engine in its most concentrated form. It takes a familiar structure, reshapes it into something far deeper, and then sustains engagement through constant decision pressure and rapid feedback. Each run presents a sequence of small, meaningful choices, where probability and strategy intersect, and where even failure contributes to understanding. The result is a system that feels both controllable and uncertain, offering just enough structure to reward skill, and just enough variation to keep every attempt alive with possibility.

Resident Evil 4

When Resident Evil 4 was first released in 2005, it marked a sharp break from its predecessors and helped redefine the third-person action genre. Its over-the-shoulder camera, tighter combat design, and emphasis on moment-to-moment decision-making became a template for games that followed.

Nearly two decades later, the 2023 remake demonstrates something more interesting. While controls have been modernised and presentation updated, the core structure remains largely intact. The systems that governed tension, resource pressure, and combat pacing are still doing the same work.

That continuity matters. It suggests that the underlying design was not just influential, but durable. And while Resident Evil 4 operates very differently from Balatro, it produces a similar form of player engagement.

Reliving the Horror

At first glance, Resident Evil 4 does not look like a mastery-driven game at all. With its linear horror narrative and immersive atmosphere, it appears to be an entirely different animal. 

In this game, encounters are largely predetermined, and the player moves through a defined sequence of environments, progressing towards a clear endpoint. Technically, this should limit replayability. Once the content has been seen, there appears to be little reason to return. In practice, the opposite is true. And the key lies in how the game constrains the player.

Combat is precise but restricted. Aiming is deliberate, and in the original version, movement is limited while shooting. Each decision carries weight. Positioning matters. Timing matters. Small inefficiencies accumulate quickly.

At the same time, resources are tightly controlled. Ammunition and healing items are scarce. Inventory space is finite, managed through the game’s grid-based attaché case, which turns storage into a secondary optimisation problem.

The effect is reinforced by the game’s pacing. Encounters escalate from controlled skirmishes to larger, more chaotic set pieces. Moments of relative calm are followed by periods of intense pressure.

Every action becomes a trade-off. Do you eliminate lower-level enemies using the trusty combat knife to conserve precious ammunition? Should you invest a rare weapon mod on your current weapon, or hold out for something better? These constraints transform the structure of the game. And, crucially, they provide players with many routes through which to approach the same set of game problems.

There are, of course, other reasons players return. For many, familiarity plays a role. The game’s setting, characters, and structure invite revisiting, whether to explore missed details, complete optional objectives, or experience the full range of its content. Completionism and nostalgia both contribute to its longevity.

But these factors alone do not explain the depth of engagement. They may bring players back, but they do not sustain repeated play on their own.

Mastery Through Constraint 

In Balatro, the player refines a system. In Resident Evil 4, they develop a form of mastery within a fixed structure.

Refinement through replay is baked into the game through the progression of difficulty modes. On starting the game, the player can choose from three difficulty settings: Assisted (a relaxed experience for novice action gamers), Standard (average difficulty level), and Hardcore (suggested for veterans of the original game). Players who beat the game on Hardcore mode unlock a hidden difficulty level: Professional. This imposes even more stringent limits on players, for example, by only allowing 'perfect' knife parries, making weapons more expensive, and enemies tougher.

On the harder difficulty levels, the experience shifts from survival to optimisation. Players learn enemy behaviours, internalise encounter patterns, and improve decision-making under pressure. With repeated playthroughs, movements become cleaner, resource use becomes more efficient, and risk is managed more deliberately.

On forums, players describe feeling under pressure but not helpless, demonstrating the careful balance the game strikes between providing a challenge and avoiding frustration. Micro-rewards are sprinkled liberally through each level, including pickups, rank challenges, and new weapons. There is almost always a nearby objective, a more optimal route, a faster clear, or a higher rank to attain, and the gameplay blends puzzle-solving, combat, horror and exploration.

Resident Evil 4 therefore demonstrates a different expression of the mastery engine, one defined not by variation or system modification, but by carefully designed constraint. The player returns not to discover something new, but to prove that they can do it better.

Moments of relative calm are followed by periods of intense pressure. The player is repeatedly pushed to operate at the edge of their capability.

Vermintide 2

Dark clouds gather over Helmgart. The Empire of Man is under siege. A band of heroes stand alone against the chaos tides...

Released in 2018 by Fatshark, Vermintide 2 is a co-operative first-person action game set in the Warhammer Fantasy universe. Players take on the roles of the “Ubersreik Five”, a group of distinct characters fighting through missions against overwhelming enemy forces.

While it shares similarities with earlier team-based shooters, Vermintide 2’s emphasis on close-quarters combat and team coordination gives it a distinct identity. At its core, it is built around a set of fixed missions, each with a defined path and objective. Players advance through enemy-infested environments, moving between checkpoints towards a final extraction point. Enemy swarms generally become denser as the mission progresses, with tougher opponents inserted for set piece fights.

In the mould of classic RPGs, players choose between different classes, with each of the five playable characters having three possible 'careers', that determine abilities and playstyles. These roles are designed to complement one another, reinforcing a genuinely team-based approach to combat.

However, Vermintide 2 has unique elements that keep players returning again and again.

Surviving the Hordes

Action is brutal and frenzied; waves of attackers crash over the players in shifting patterns. Ranged weapons are available, but melee combat is front and centre. Players must block and dodge, and choose between light and heavy attacks. Cleave determines how many enemies a strike can pass through, while certain armour requires specific types of attack.

Blows land with real weight, enemy reactions are immediate, and successful control of a swarm produces a clear sense of momentum. This creates a steady stream of micro-rewards, even in the context of familiar encounters.

Special 'elite' enemies, such as the heavily armoured Chaos Knights, are designed to disrupt this rhythm, breaking formations, and isolating players, making them vulnerable to other forms of attack. Survival, therefore, depends on rapid coordination, rather than individual skill.

Enemy spawns vary from run to run, altering the flow of each mission. Even within fixed environments, small differences in timing, positioning, and team response can produce entirely different outcomes.

After each completed mission, players are presented with a scorecard that allows direct comparison with their teammates. This lightly competitive aspect motivates players to refine their tactics and execution for the next run. In this sense, missions become co-authored survival stories, providing anecdotes and ammunition for social interactions.

Mastery Under Pressure

This layered combat system - and the wide variation in how encounters unfold - is central to Vermintide 2’s longevity.

Unlike Balatro, where players refine a controlled system, or Resident Evil 4, where encounters are fixed, Vermintide 2 demands execution under changing conditions. Mastery is not simply about making the right decision, but making it reliably as the situation evolves.

At higher levels, this produces a distinctive rhythm — a controlled form of chaos in which blocking, dodging, and striking fall into a repeatable cadence under constant threat. As difficulty increases, this loop tightens. Margins for error shrink. Precision and awareness become essential.

In this sense, Vermintide 2 extends the mastery engine into a social and dynamic space. It is not about building a better system, or optimising a fixed sequence, but about surviving pressure together, with increasing precision.

Players return not primarily for new content, but to perform more effectively within what already exists.

Why Mastery Engines Engage Players

Across these examples, a common pattern emerges, not in what the games are, but in how they hold attention over time.

Each presents a different form of mastery - from system construction, to execution within constraint, to coordination under pressure. The structures differ, but the underlying dynamic is consistent: outcomes are clear, feedback is immediate, and improvement is visible. Repetition has a tangible benefit, and each attempt provides experience that can be applied to the next.

This shapes the nature of engagement for these titles. Time spent is not simply consumption, but investment in understanding. Players return not primarily for new content, but to perform more effectively within what already exists.

Of course, this form of engagement is not universal. It attracts players motivated by incremental improvement over novelty, and it relies on clarity. If outcomes feel arbitrary, or feedback is obscured, the loop breaks, because players cannot refine what they cannot understand.

When mastery engines work, however, the effect is durable. These hidden systems allow relatively small or constrained games to sustain high levels of engagement, compared with much larger titles. They do not need to offer more; they need to offer depth of progression. And for players willing to engage on those terms, that depth is often enough to keep them returning, long after the content itself has been exhausted.

In the next article in our series on game engagement systems, we look at those games that keep players involved through Generative Social Systems.

Series: Secrets of Engagement

The Hidden Systems of Engagement Engagement Insights from Steam Data Five Systems of Engagement Series Conclusion: What Keeps Players Playing? 1. Mastery Engines 2. Generative Social Systems 3. Creative Stewardship Systems 4. Persistent Stakes Systems 5. Fantasy Anchors