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The Complexity of a Casual Game

Since so many people seem to be surprised that Spore, a game that mixes all sorts of game genres into one game, didn’t create the ultimate experience for each of those sub-games, and Will Wright’s recent interview with MTV in which he claims that Spore was meant to be a casual game:

“I’d say that’s quite accurate,” Wright told me. “We were very focused, if anything, on making a game for more casual players. “Spore” has more depth than, let’s say, “The Sims” did. But we looked at the Metacritic scores for “Sims 2?, which was around 90, and something like “Half-Life“, which was 97, and we decided — quite a while back — that we would rather have the Metacritic and sales of “Sims 2? than the Metacritic and sales of “Half-Life.”

And one way of getting there is to present a narrower range of options than a hardcore player might be expecting?

“Yes,” he said. “Part of this, in some sense was: can we teach a “Sims” player to play an RTS [or Real Time Strategy game]? … I think the complexity we ended up with was toward that group.”

So reducing the range of options is one way to make a game more casual, but what options are we talking about? I think there are two ways in which you can look at a game’s complexity: input complexity and rules complexity.

With input complexity, the available interface options are limited. For a complex input scheme, look at NetHack. There is a command for drinking, and one for eating. One for putting on armor, and one for equipping weapons, and one for putting on a ring, and entirely different commands for taking them all off again! Attacking can use any number of commands to kick, throw, fire an arrow, zap a wand, or swinging your weapon. NetHack is definitely NOT a casual game, but look at FastCrawl for a more accessible game. Instead of requiring the player to know every function of every button, key, or icon, you limit the interface. Technically Tetris can be played with three functions: move left, move right, and rotate piece. It’s not a mindless game, though. You can employ various strategies at various stages of the game. There is complexity, but it is hidden behind a simple interface. This combination makes it an accessible game, as the success of the GameBoy with children and adults alike can attest to. For another example of a simple interface, see Fishie Fishie. From the creator’s page:

Yesterday I played a game that had three different buttons for “jump”. Three! I mean, really, what’s happened to the world? How am I supposed to keep an eye on the kids, stay up to date with current affairs, and remember which button to press when I want to esape the toothy maw of an airborne crocodile? In protest I built Fishie Fishie, a game you play using exactly one button.

Rules complexity deals with what’s happening in the game itself. If you’ve ever played the Buffy the Vampire Slayer board game, you know what I mean when it comes to complexity. The interface is simple and familiar enough: roll dice, move players, attack other characters. But then you have to keep track of hit points, goals, who is a vampire when, and yes, the current phase of the moon! And if you’ve never played Dungeons and Dragons, just keep in mind that choosing your character’s class, alignment, feats, skills, and armor is what you do BEFORE you start playing. If you’re playing a cleric, trying to turn the undead will result in moans from the other players since play basically STOPS until you do all the complex calculations to figure out how many ghouls at what strength you turned or destroyed. Now compare these rules to the “0 player” Game of Life. There are only four rules, and yet the ways these rules interact, the dynamics of the game, are rich and complex.

Buffy could have taken a lesson from the card game Fluxx. In Fluxx, the rules change constantly as you play since played cards can add, change, or remove rules. Even though you would think it would be too complex and only appeal to the geeky, in my experience it seems that everyone loves it. I think a key part of it is that the rules aren’t hidden away in a manual but right there on the cards in front of you! You can walk away from the game to get a snack while the rest of the players take their turns, and when you get back you know exactly what the state of the game is just by checking the cards. An otherwise complex game made casually accessible by its interface!

Perhaps Buffy fails to appeal to playing fans not because it is too complex but because this complexity is hard to understand just by looking at the game. Every time you pull the game out of the closet, you have to re-remember the rules before you start, and usually that means someone has to read the instructions, if they still exist. Throughout the game, you have to periodically consult the instructions to clarify what to do in certain situations. With Fluxx, you can just start playing.

So can you make a complicated rule-set accessible by limiting the interface? Can you reduce the rules of the game to a handful and make an otherwise complex game easier to grok? It seems that if the rules are simple, the interface can also be simple, but if the rules are complex, the interface doesn’t have to be. If you believe that reducing complexity is key to making a game more casual-friendly, I believe you can still make otherwise hardcore games more accessible by making the interface intuitive and simple.

[tags] indie, casual game, game design [/tags]

2 replies on “The Complexity of a Casual Game”

This brings up a good discussion regarding game complexity.

Consider a game to be a system, S. You can think of S as the rules of the game. S is a system of rules that can be modeled as a black box having input I and output O.

In the classic control system model you would then have :

IS = O

This basically means that the output of a system can be described as the product of input to the system and the inner workings (rules) of the system. Therefore the system model (rules) can be thought of as:

S = O/I

This simply means that the complexity of a system (the system model itself) is equal to the ratio of output complexity to input complexity. So as input complexity goes to zero, system complexity goes to infinity which is the definition of chaos and this works out well in our model. This would be equivalent to pulling the controller from the game console which means you have no control over the outcome of the system. However, it is safe to assume that this system can not exist perpetually. A system whose output is non-zero and has input of zero is also known as a perpetual motion device and via conservation of energy cannot exist in nature.

On the other hand, as output complexity goes to zero, complexity also drops to zero. Imagine the system is a vacuum or an open circuit (an infinitely long suspension of an OS that does nothing no matter what the input). In this case, no matter what you put in, you get nothing out.

Another way of stating the above analysis is to say that complexity is directly related to predictability. If the outcome of a system is predictable then it is safe to say that the complexity of the system is low. However, if outcome is less predictable the system is more complex.

Chess is hardcore and checkers is casual. In chess, the outcome of the game is very hard to predict and many players have tried to figure out the formula for winning but it tends to be a lost cause. Checkers on the other hand is a much more predictable system.

I think that hard core games tend to have complex input and of course, much more complex output. But there are are exceptions to this and there truly can’t be a formula that resolves a game to be hard core or casual because they are not divided by a clear border. However, I do think it is safe to say that a game with low input complexity will tend to be casual. For instance, the input in checkers is far less complex than that of chess since all of the pieces are created equal. You don’t have many options on your turn in checkers. In chess, there is complexity in movement of each type of piece. Just because the input in a checkers game is simple does not mean that the output is simple. In fact there are infinite ways to win a game of checkers. However, the simplicity of input makes it easy to learn to play and therefore more accessible to everyone. The complexity of the outcome in checkers is what makes it such a good casual game.

Now to finally answer your question:

So can you make a complicated rule-set accessible by limiting the interface? Can you reduce the rules of the game to a handful and make an otherwise complex game easier to grok?

I think the questions are answered by example. Take a look at Geometry Wars. The input is fairly simple. However the outcomes are wildly unpredictable. The rules of Geometry Wars are pretty complex and many interactions take place that change the outcome of the system. Very high output complexity and low input complexity make this a very popular casual game. I don’t think that making a game casual means you have to make the game system less complex. In fact, it may be better to make the game system as complex as possible while keeping input complexity to a minimum in order to maximize complexity and meaningful play when making a casual game.

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