Core Game Loops

Definition

The core game loop is the set of actions in a game that most players will spend most of their time doing — the most frequent and repeated actions players take. Tim emphasizes that you can usually identify a game's core loop within an hour of playing it, watching a streamer play it, or trying a demo. If you can't figure it out in an hour, the game may have a problem.

Core Game Loop vs Design Pillars

Tim draws a clear distinction between core game loops and design pillars (which he covers in a separate video):

• Design pillars explain how every feature in the game serves the game's guiding principles
• Core game loop identifies which of those features players will actually experience most of the time

The core game loop should touch on all design pillars, since it's where players spend most of their time. Peripheral features can occasionally miss a pillar, but the core loop cannot afford to.

Same Genre, Wildly Different Loops

Even within the same genre, core game loops can be completely different. Tim uses fantasy games as an example:

• Tactical combat game — the loop is entirely about selecting units, choosing actions, executing combat
• Exploration game — the loop is about traversing and discovering the world, with minimal fighting or dialogue
• Narrative game — the loop centers on conversations with NPCs, reading books, interacting with terminals

Saying "fantasy game" or even "RPG" tells you nothing about the core loop.

Player Build Dependency

In Tim's own games (Fallout, The Outer Worlds), the core game loop depends on the player's character build. Some players fight through everything, others talk, others stealth. No single action applies to all players, but when you group them together, you can say most players will do most of these things most of the time. This makes the loop harder to define but more important to get right.

Why Define It Early

Team Focus and Prioritization

The core game loop tells your entire team what to focus on. It helps production staff decide what to prioritize — core loop features must ship, while other features are like side quests that can be cut if time runs short.

Optimization and Bug Fixing

At the end of development, the core loop tells you where to spend optimization time. These features need smooth UI, good frame rates, and zero bugs. An obscure crafting bug can wait; a crash triggered by basic combat cannot.

Publisher Defense

Tim highlights a particularly practical use: the core game loop is a powerful negotiation tool with publishers. If a publisher suggests unwanted features (e.g., microtransactions), you can respond: "We don't see a role for microtransactions in this game's core game loop." This forces the publisher to either figure out how it fits (they probably can't) or ask you to change the core loop — at which point you can point out that means redesigning the entire game.

Bigger Loop, Bigger Cost

Tim warns from experience: the bigger your core game loop, the harder it is to implement. Games that let players fight, talk, stealth, and use companions through every situation have massive loops that translate directly into bigger schedules, bigger teams, and more money. It's always in your best interest to keep the core game loop as laser-focused as possible, even though some games will inevitably have large ones.

References

• Tim Cain. YouTube video. https://www.youtube.com/watch?v=aDE69s3pp7M