Games are made of rules.

This is not a metaphor—it is their essence. Much like how the board and pieces in chess mean nothing without the conditions that govern their moves, games are defined not by their visuals or assets, but by the logic that binds them. The Rule Book by Jaakko Stenros and Markus Montola reminds us that rules do not merely constrain—they construct. They produce meaning. They form institutions. They breathe life into inert materials, like a carved wooden king imbued with deontic powers the moment we agree to play.

Consider chess. Two players. That’s a rule. Taking turns. Another rule. White moves first. Rules cascade, creating not just mechanics, but a culture of play. The queen does not move diagonally and in a T-shape (a correction: she moves diagonally and along ranks and files)—not because she is a carved figure of power, but because we all agree she can. She can, because the rules say she can. And in that saying, we believe.

Rules are the building blocks of play. Formal rules are the most familiar: the written procedures in a rulebook, the algorithm in a game engine, or the official regulations of a tournament. They define the intended structure of play and dictate what players can and cannot do. Formal rules are the explicit, codified instructions—what’s written in the manual or encoded in the system. In a high fantasy RPG like The Elder Scrolls V: Skyrim, the rules define that wielding a two-handed sword consumes stamina, or that you must reach level 50 to unlock certain perks. These mechanics are not open to negotiation during play—they structure the game world and your interactions with it.

In contrast, internal rules reside in the player’s own intent—self-imposed constraints or goals, like refusing to use certain weapons or choosing to roleplay a character’s moral code. Internal rules arise from the player’s own volition, forming private constraints or goals. A classic example is speedrunning—where players voluntarily skip dialogue, exploit glitches, or reject the intended pacing to finish a game like Super Mario 64 in record time. The game never asks them to do this—it’s a layer of challenge and ritual they impose themselves.

Surrounding the act of play are social rules—the shared norms and etiquette that govern behavior among players. These unwritten understandings decide what’s fair, what’s fun, and what’s frowned upon. Social rules emerge from the culture surrounding play. In tabletop Dungeons & Dragons, players often agree to stay in character, avoid “meta-gaming,” and maintain narrative tone—unspoken rules that preserve the immersive, collaborative experience. Even in competitive games like Street Fighter II, informal norms against "spamming" a move too often can shape the flow of combat more than any code.

External regulation, meanwhile, comes from institutions beyond the game itself: laws, licensing, parental controls, or platform policies that can limit or reshape gameplay. External regulation introduces constraints from beyond the game. For instance, World of Warcraft may feature age-based restrictions, regional content censorship, or real-money trading rules imposed by Blizzard or local governments.

And beneath it all are material rules—the physical and technical constraints embedded in the world. Whether it’s gravity making a Jenga tower fall or collision boxes defining where a digital character can move, these rules are not socially negotiated but rather imposed by the medium itself. Material rules stem from the physical or digital substrate that makes the game possible. The rules of gravity in Jenga, the limitations of movement in Super Mario Bros., or the way Unity or Unreal Engine simulate physics and collisions—these aren’t authored by a designer in the traditional sense, but emerge from the properties of materials or code. In a digital game, the engine is the hidden architect: it governs what is renderable, measurable, and possible.

So rules, as The Rule Book argues, are not monolithic. They are made out of 5 dimensions, each emerges into a game:

Formal rules are explicit procedures—what you find in a rulebook or game code. In chess, a formal rule states that the knight moves in an L-shape—two squares in one direction, then one square perpendicular. Another formal rule dictates that white always moves first.

Internal rules are private agreements we make with ourselves—like choosing to do a pacifist run. In Super Mario 64 speedruns, an internal rule might be completing the game with only 16 stars, even though the game allows for 120. The player chooses this constraint to challenge themselves, not because the formal rules demand it.

Social rules are the etiquette and expectations around play—when to talk, how long to think. In Settlers of Catan, a classic social rule is not taking excessively long turns or over-negotiating trades—while not forbidden by the formal rules, doing so can frustrate others and break the social flow of the game.

External regulation comprises legal or institutional limits—age restrictions, EULAs. In Grand Theft Auto V, regional laws have led to censorship in some countries—such as Australia banning or altering certain missions due to depictions of violence—demonstrating how external regulation can directly shape what content is accessible in a game.

Material rules are physical or digital constraints—gravity in real life, collision boxes in software. In Skyrim, the Havok physics engine defines how objects fall, bounce, or ragdoll—granting the world a sense of weight and motion, but also revealing limitations when bodies jitter unrealistically or items clip through terrain. These constraints are not designed behaviors, but material rules emergent from the engine’s simulation fidelity.

A game, then, is not one system—it is a choreography of systems. It is the meeting point between formal instruction and social improvisation, between code and culture. And when these systems entwine, emergence happens. Out of the rigidity of logic comes the unpredictability of play. The player, once bound by constraint, discovers freedom. Not in escaping the rules, but in expressing within them.

This is the paradox of systems: they create freedom through structure. A well-designed rule is not a limitation but a provocation. It invites the player to explore boundaries, to test logic, to generate meaning from limitation. The Rule Book calls this “constructionist ludology”—an approach that sees games as socially constructed institutions, born from the interaction between rules and players, and situated within culture. A game is not simply played; it is enacted. Enacted by people who choose, for a moment, to believe that a plastic coin holds value or that a digital sword is worth pursuing.

The question, then, is not how to follow rules—but how to write them.

Game mechanics, as the book explains, are not singular rules but aggregates—bundles of formal and material rules working in concert. Raph Koster describes them as structured experiences involving input, processing, and feedback—like a jump in a platformer: you press the button, the avatar arcs through the air, and gravity—encoded as a material rule in the engine—pulls them down​. So when we say that a physics engine shapes gameplay, we are acknowledging that the material rules—friction, gravity, collision—form the substrate of mechanics. Thus, the game engine enforces the world we'd imagine it to be. In this view, mechanics are the dance between rule and experience—between formal instruction and physical constraint. A jump, a shot, a swing of the sword: each is a mechanic, made tangible through rules, and made real through materials.

Thus, mechanics are best understood as systems made from rules—specifically, interacting rules that form a coherent pattern of play. A rule is a single constraint or prescription: “You may only move diagonally.” A mechanic emerges when multiple rules interact: “Movement + stamina cost + terrain penalty” = a movement mechanic. So, rules are the ingredients. Mechanics are the recipes. Systems are the meals

As game designers, our role is to design mechanics that foster transformation. We write rules not simply to restrict, but to provoke expression. We design mechanics not only to entertain, but to awaken agency, invite reflection, or stir something deeply human. Rules, in the hands of thoughtful design, become instruments of playfulness, and when tuned into mechanics, they sing. Take the sanity mechanic in Amnesia: The Dark Descent. As the player lingers in darkness or witnesses disturbing events, their sanity deteriorates—causing screen distortions, auditory hallucinations, and loss of control. This isn't merely a health bar rebranded; it’s a mechanic designed to induce fear, vulnerability, and tension. The formal rule is simple: “Avoid darkness to maintain sanity.” But when embedded within the material rules of lighting, monster behavior, and limited resources, it becomes a mechanic that forces players to fear the very hiding spots that would otherwise keep them safe. In this way, the mechanic doesn’t just simulate fear—it enacts it to the player.

In Papers, Please, you play as a border inspector in a fictional authoritarian regime, stamping passports under time pressure while trying to earn enough money to feed your family. The core mechanic—reviewing documents and making binary choices to approve or deny entry—starts as simple bureaucracy. But as the rules evolve, moral complexity deepens: Do you follow orders and deny a mother entry, even though her child was just approved? Do you help a fleeing couple reunite at the cost of your own job? These decisions are not delivered through cutscenes or narration—they are embedded in the mechanic of inspection. The game transforms a repetitive task into a ritual of ethical tension, allowing players to construct their own meaning in the face of systemic pressure. The mechanic doesn’t preach—it asks you to choose, and through that choice, meaning emerges.

In classic arena shooters like Quake III Arena or Unreal Tournament, the core loop is brutally simple: frag or be fragged. The mechanics—fast movement, precise aiming, weapon pickups, and spawn timings—create a space where reflex, map control, and psychological pressure intertwine. Every kill, every flick shot, every mid-air rocket hit becomes a social signal—a declaration of skill, dominance, even identity. The formal rule may be: First to 25 kills wins. But what emerges through the mechanic is far more primal: a visceral sense of triumph, of “I outplayed you.” There’s no scripted narrative, no dramatic soundtrack—only the pure mechanical tension of movement and mastery, where every win is a self-authored legend. Mastery of the mechanic becomes self-expression; victory becomes identity. This is the power of well-designed mechanics: they do not just support gameplay—they channel emotion, they provoke ego, they construct memory.

Rules are not merely scaffolds for games—they are seeds of experience. From them grow mechanics, and from mechanics bloom emotion, agency, culture, and play. Each mechanic we encounter—be it a jump, a puzzle, or a boss fight—is not an isolated feature, but the visible flowering of invisible constraints. We are shaping how people act, feel, and reflect within imagined worlds. And at the foundation of it all are rules: the subtle scripts of interaction, the quiet grammar of possibility. To think in systems is to think in rules, and to think in rules is to think in meaning.

So let us not overlook them. Let us tune them like instruments. Let us write rules not to restrict—but to awaken, to provoke, to play. For when rules resonate, mechanics emerge. And when mechanics sing, the game becomes more than play—it becomes alive.

Exercises

1. [🟢 Remember] Identify the Five Rule Types
List and define the five types of rules described in The Rule Book: formal, internal, social, external, and material. For each, write down a game example that illustrates how that type of rule shapes play.

2. [🟢 Understand] Explain Mechanics as Systems
In your own words, explain how rules combine to form mechanics. Use an example (like movement, crafting, or combat) and break down the interacting rules that give rise to it.

3. [🔵 Apply] Reverse-Engineer a Mechanic
Pick a mechanic from a game you enjoy (e.g., stealth in Metal Gear Solid, building in Minecraft). What formal, material, and possibly internal rules are working together to create that experience? Diagram or describe the rule system behind it.

4. [🔵 Analyze] Map Emergence in Play
Describe a moment in a game where something unexpected or emergent occurred—something not scripted, but made possible by the rules. Which systems enabled it? What rule types were at play, and how did they interact?

5. [🟠 Evaluate] Critique a Game's Rule System
Choose a game with strong systems design (e.g., Dark Souls, Civilization VI, Overwatch). How well do its rules provoke mastery, meaning, or emotion? Does it rely too heavily on one rule type over others? Does its design invite player expression or restrict it?

6. [🔴 Create] Design a Mechanic of Emotion
Invent a new game mechanic designed to evoke a specific emotion (fear, awe, guilt, serenity, etc.). Describe the core rule interactions that support it. What kind of player experience would emerge from it, and why?

7. [🔴 Create] Build a System of Rules
Design a microgame (on paper or in text) that includes all five rule types: formal, internal, social, external, and material. How do these rules layer into a mechanic? What does the player learn or feel by playing within them?

8. [🔴 Create] Write Your Systems Design Manifesto
Inspired by the essay, compose a short paragraph that outlines your personal philosophy as a systems thinker and game designer. What kind of rules do you want to write? What kind of mechanics do you want to unleash? What truths do you want to emerge through play?