Subtractive Design
(This article originally appeared in Game Developer Magazine.)
Subtractive design is the process of removing imperfections and extraneous parts in order to strengthen the core elements. You can think of a design as something you build up, construct and let grow, but it’s pruning away the excess that gives a design a sense of simplicity, elegance, and power.
"Make everything as simple as possible, but not simpler." —Albert Einstein
First let's look at the theory behind this idea to see why designers in many fields often think in terms of negatives (subtracting things) rather than positives (adding things). Then let's look at several successful subtractive designs so we know what to aim for. Finally, I'll discuss why subtractive design often breeds controversy.
Why Subtraction?
Designers in many fields, not just games, often think in terms of negatives (subtracting things) rather than positives (adding things). Design is creating a form (a game in our case) that fits a context. There isn’t just one boundary we have to check between form and context though, there are infinitely many. Is our game easy enough to learn? Does it have the desired amount of strategy or depth? Does it appeal to the intended age-group? Is it cheap enough to make in both time and money? Is it aesthetically pleasing? Do the aesthetics help the player understand how to play the game? Do the mechanics work well with each other? Do they require the desired amount of dexterity? The list goes on.
We first come up with a design that might fit all the requirements. Sometimes this comes from the intuition of a designer who has internalized all those forces and somehow spits out a new answer. More likely, we start with something pretty well established so that we know it solves many of the requirements already. That’s how genres, sequels, and remakes help us make good (but not necessarily new) designs.
Once we have something, we have to evaluate how good our design is. Does our form actually fit the context? Architect Christopher Alexander had some choice words on this subject in his Notes on the Synthesis of Form:
We should find it almost impossible to characterize a house which fits its context. Yet it is the easiest thing in the world to name the specific kinds of misfit which prevent good fit. A kitchen which is hard to clean, no place to park my car, the child playing where it can be run down by someone else’s car, rainwater coming in, overcrowding and lack of privacy, the eye-level grill which spits hot fat right into my eye, the gold plastic doorknob which deceives my expectations, and the front door I cannot find, are all misfits between the house and the lives and habits it's meant to fit. These misfits are the forces which must shape it, and there is no mistaking them. Because they are expressed in negative form they are specific, and tangible enough to talk about.
Alexander explains that when a misfit occurs, we are able to point at it specifically and describe it. When we instead try to explain what a good fit would be like, we’re often reduced to generalities that are hard to act on.
With this in mind I should like to recommend that we should always expect to see the process of achieving good fit between two entities as a negative process of neutralizing the incongruities, or irritants, or forces, which cause misfit.
/// Ico
When Fumito Ueda designed Ico, he did not start with a list of everything the game should have. Instead, he started with the core idea that it should be