Core Loop

When you think of a game, you probably think of a sprawling sci-fi world or a frantic multiplayer battle or blocks falling out of the sky. When I think of a game, I think of a circle. Maybe a few circles.

One of the most famous-in-development-circles quotes is Jamie Griesemer's quote,

"In Halo 1, there was maybe 30 seconds of fun that happened over and over and over and over again. And so, if you can get 30 seconds of fun, you can pretty much stretch that out to be an entire game."

If you hit up the link to the Joystiq article above, he talks about the quote in a bit more depth, and how games are those 30 seconds with variations. When you give it some thought, a lot of (if not all) games can be broken down in this way. There's another quote, and unfortunately I have no idea where I'd originally heard it - I think it came up in a discussion I was having with someone at GDC or at an IGDA meeting or something, but it went something like this:

"Figure out what you're doing most of the time. That's what your game is. Make that fun."

This was really eye-opening for me at the time, and it's something I've never been able to shake. This is distressing, because once you're in that mindset, you see a lot of games doing things very, very badly. Two examples:

  1. Assassin's Creed - one of the main things you do is navigate a city. You're given a tremendous number of ways to get around. Climb up a building. Swing across a gap on a pole. Jump from rooftop to rooftop. Weave through a crowded street. You always have choices to make about how to get around, and getting around is a really engaging experience. You also fight, plan assassinations, search for things, chase stuff - all of those things are built off of the basic engine of navigation & character movement.
  2. Final Fantasy XIII - one of the main things you do is navigate a world. You can walk forward on a fixed corridor in which nothing much happens. It's pretty, sometimes. You're often unexpectedly interrupted by narrative cutscenes that look dramatically different than the in-game world you're traversing. Characters do exciting things in the cutscenes like fly around and run. In-game, you cannot jump. You will also fight, which has absolutely nothing to do with moving around during the rest of the game. You will explore, but since all you can do is walk around, "finding things" basically just means "walking up to them."

In Assassin's Creed, they spent a tremendous amount of time building up the systems that support the thing that you're doing most of the time. In Final Fantasy XIII, they spent a tremendous amount of time making scenery nice to look at, and virtually no time on the mechanics of the thing that you're doing most of the time. Which isn't necessarily FFXIII's biggest problem (it's a game full of ENORMOUS PROBLEMS), but it's a huge one.

A hybrid is something like Call of Duty - navigation is basically limited to walking, running, jumping, and periodically vaulting, and it's almost always done in a completely linear corridor - but they spend a LOT of time making it feel visceral and exciting, to the point where "Walk from point A to point B in a rigidly prescribed manner" is still generally entertaining. Then the multiplayer game is quite different, because it's nonlinear, and threats come from everywhere.

Both of these, the idea that a game is 30 seconds of fun, and the need to focus on the thing that the player is doing most of the time is captured in the idea of the "core loop" of a game. This is a simple description of what the 30 seconds entails, and what you assume is that a player will traverse the core loop many, many times as they play, so you need to be able to introduce meaningful variation into how the player traverses the loop over time.

Take The Sims. Its core loop is pretty simple:

  • Fulfill your Sim's motives (their personal needs like staying clean and sleeping)
  • Go to work (how "well" you do at work is related to how well your motives have been fulfilled and how many friends you have)
  • Earn Money (which you can use to buy stuff)
  • Buy Stuff (which lets you fulfill your motives faster)
  • Make friends (in the time you're not spending fulfilling your motives, it's also affected by how well you are fulfilling your motives, and you need friends to progress at your job)
  • Repeat

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Basically, each step in the loop affects the other things in the loop, and as you go through it, you do better at each bit of it. Over time, you earn money. So you get better gear. You can now fulfill your motives faster. You can make friends in the increasing free time you have, so you can get promoted and get a better job and earn more money to buy more stuff to fulfill your motives better and on and on and on ad infinitum. Which is why the Sims is fundamentally a joke about the treadmill of consumer culture. But it's also 30 seconds (more or less) repeated over and over, with variation.

Halo is fundamentally similar:

  • Enter a room
  • Assess the space you're in
  • Kill your enemies
  • Take their weapons
  • Move on to the next room

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Seems relatively simple. But the variation in the spaces, the variation of the enemies, the tools at your disposal, and the weapons make this constantly engaging over the many hours of entering rooms & shooting things. Every part of the loop changes over time & "improves".

When you're developing a game, the more "efficient" you can make this loop - the more things it can affect, or the more things tightly tie into it - the better your game is. Why? Because if you invest the time to build up the most important systems in your game with the most resources, and you ensure that the basic mechanical foundation of your game is excellent, that bleeds into every other element of the game. It has to.

The first Assassin's Creed was not a great game - but it laid the foundation for Assassin's Creed 2, which built directly off of that foundation to create an extraordinary game. They were able to do that because they invested so much in building things fundamental to that loop. I'd argue that more recent Assassin's Creed games have been disappointing because they haven't improved the foundation in any significant way. With the exception of the pirate ships in AC: Black Flag, the basic core of environmental traversal is now nearly a decade old, and for it to achieve greatness similar to AC2, they need to revamp the entire concept of how environmental navigation is handled, instead of continually building new branches on a decaying trunk.

So yeah - next time you play a game, think about the "core loop". What are you doing most of the time? What is the 30 seconds that get repeated again and again with variation? How does the variation change the experience over time?

Then there's also the question of how your increasing understanding and mastery play into that experience. Mastery & challenge are interesting concepts, particularly in the world of mobile games. Done right, mastery is a powerful concept. Done wrong, it's punitive, awful, time-wasting and frustrating. Maybe we'll talk about that next.