What Is a Core Game Mechanic? A Plain Explanation
A core game mechanic is the action, or small set of actions, that players repeat throughout a game and that the rest of the game supports. In a footrace it is running, and in a first-person shooter it is moving, aiming, firing and managing supplies, all working together.
Where does the term come from?
The usual reference is the book Rules of Play by Katie Salen and Eric Zimmerman. As Karl Kapp quotes it, a core mechanic is the essential play activity players perform again and again. Zimmerman says in a separate essay that nearly every game has one.
How is a mechanic different from a rule or a system?
People use these words in different ways. Here is a simple set you can use with your AI:
| Word | Meaning | Example |
|---|---|---|
| Rule | What is allowed | You can jump only from the ground, or if you have an air jump left |
| Mechanic | An action that changes the game | Jumping |
| Core mechanic | The action the game is built around | Jumping, in a jumping game |
| System | Several mechanics working together | Stamina limits sprinting and climbing |
It also helps to tell apart what you build from what players feel. A well-known paper by Hunicke, LeBlanc and Zubek separates three layers: the parts of the game, what those parts do while people play, and the feelings this creates in the player. You build the first. Your players experience the last. Only playing shows you whether the two match.
How do I find the core mechanic of my game?
These are working tests and not a formal method:
- Count. What does the player do most often, minute by minute?
- Remove it. If you took this action away, would anything recognisable remain?
- Look at what feeds it. Levels, enemies, upgrades and rewards usually give the core action new reasons to happen. If nothing feeds an action, it is probably secondary.
- Name it as a verb. If you need more than a few verbs, you may be describing the whole game and not its core.
- Build it alone. Ask your AI for only that action, with simple placeholder art. If it is not interesting after a few minutes, more content is unlikely to fix that.
Can a game have more than one core mechanic?
Yes. The shooter example above is four linked actions. What matters is that they form one loop the player repeats. Two loops that never touch often feel like two games, so make that choice on purpose.
How do I describe a core mechanic to my AI?
Write it down in plain words, so your AI builds what you mean. Say what the game has to remember, which numbers you can tune, what must always be true and what should happen in odd cases. Here is a short example for a double jump:
- The game remembers: whether you are on the ground, and how many jumps you have used.
- Numbers to tune: you get 2 jumps.
- Always true: you never use more than 2 jumps. Landing gives them all back.
- Odd case: when you walk off a ledge, does that cost a jump? Decide.
The last line is where a description earns its keep. Leave it out and your AI picks an answer for you, and you may not notice for weeks. So when it says it built what you described, ask it to show you where that is written, line by line.
The game ideas in our library are written down like this, with examples and tested starting values. Use them as a starting point, and keep your design your own. Once you have your description, My game keeps breaking shows how to keep it working as you add more.
Can a core mechanic be owned?
Copyright generally does not protect a mechanic as such, though the law is more detailed than that, and patents are a separate question. We do not say that any specific mechanic is free to use.