Core Loop

The Core Loop is probably the most basic of design tools; and one of the most powerful ones. In essence it represents the fact that in order to engage players in a game, their actions (or verbs) need to lead seamlessly to a future verb, which will lead to a third, etc… If these actions then loop back around to the first one, then a player will not find a natural stop to the game and can potentially play for huge amounts of time.

A core loop is a simple diagram that shows the player actions during the game, briefly explaining how they feed into each other. It is, by design, a zoomed out view of the game, and it’s not meant to explain the game in detail. However, it is very useful to make sure you are not overdesigning, and as a gut check that the game has the mechanical consistency to keep players engaged. It also helps focus production, as it highlights which aspects of the game are fundamental.

It is important to keep the core tight and as small as possible for the gameplay to exist. Bloat is a real problem that won’t rear it’s ugly head until much later in production. I’ve seen cores as simple as 2 elements to as complex as 5; but that’s already pushing it in my opinion.

A quick note on the type of verbs you want to use here. These verbs are broader than direct player actions, and might even serve as goals in their own right. For example, while shoot and jump are common player actions, engage in combat and explore are better descriptors of a core element of the game.

The core loop is pretty old, the earliest writing I’ve found is from Richard Rouse III’s Game Design: Theory and Practice, but it’s likely older.

1. Write down the main verbs a player is going to do in a game.
2. Arrange them in a circle
3. Think and describe how one will lead to the other.

Let’s imagine that we are working on a Bullet Heaven game (also known as Action Roguelikes) such as Survivor.io.

If we were trying to analyze it’s core, the main verbs would be: Kill, Collect & Upgrade. Placed in a Core Loop, it would be presented as:

Notice how the description of each verb tells us how it connects to the next one. Having this transition be incredibly intuitive is the sign of a good, solid core.

---