One of my favorite games, at least from the standpoint of discussing game design principles, is Monopoly. It's a game with elements of both skill and chance; it's easy to analyze how resources flow in it; and it has the advantage that almost everyone in the western world has heard of it. When I use Monopoly as an example, I can be pretty confident that other people are going to know what I'm talking about. The names of the streets are different depending on what country you're playing in, but the principles are all the same.
Monopoly is a simplified game about trading real estate – simplified because all the complexities of actually buying real estate aren't included. There aren't any inspections, or insurance, or taxes to worry about. Monopoly retains the fun aspects of trading real estate, and ignores the parts that aren't fun.
Like symmetry and balance, simplification is a fundamental game design principle. Simplification is the vital difference between a game and a simulation. The object of a computer simulation is to model a real system as closely as possible in order to study its behavior under different conditions. The object of a computer game is to entertain, and other considerations are secondary. Reality is complex and difficult. Games are supposed to be easy and fun. To get from one to the other, you have to simplify.
Game players demand varying degrees of realism, and it depends a lot on the genre of game that they're playing. In most shoot-em-ups, for example, the players don't want to think about the effects of gravity or crosswinds on their bullets – they want to point at a target and hit it. On the other hand, people who play military games based on real equipment want that equipment to behave just as it does in real life. For them, a lot of the fun of the game comes from knowing that what they're doing is "just like" the real thing – even if it's complex and difficult to master. Try playing a modern fighter aircraft simulator with the "maximum realism" settings turned on, and you quickly find out why very few people are actually able to fly fighter aircraft, and why it takes months of training to learn how to do it.
Many computer games today contain some of the elements of storytelling: a setting, a conflict or problem, and perhaps some characters. Fiction is itself a simplification of the real world, a telling of a story without including every possible detail. You can easily see the effects of this on TV, especially in soap operas. Two people will be having an argument, and one of them will reveal some shocking fact that was unknown to the other. The camera moves in for a dramatic close-up. The music plays a sudden, loud chord, and we see the other person looking amazed or horrified. Everything tells us that this is a Significant Moment. We cut to a commercial.
Except, of course, that that's not the way it happens in real life. In real life, when someone reveals something shocking during an argument, the other side demands an explanation, and the argument continues. Discussions don't just cut off in the middle during a Significant Moment; they're either resolved, abandoned, or interrupted. The writers of television shows, severely constrained for time, leave out the messy truth about human conversations. That's also why people in TV never say goodbye before hanging up the phone. The narrative doesn't really require it, and it takes time.
Representational art simplifies the real world as well. It includes what the artist thinks is important and omits what the artist thinks is irrelevant. The object is not to present the scene exactly as it would appear if the viewer were there; the object is to present it as the artist chooses to portray it. Even photography is a simplification of sorts: the act of putting a frame around an image is an act of editing, of choosing to show one thing and not another thing. And with computer-generated graphics, the simplification is particularly noticeable unless special care is taken. In most computer-generated scenes the light is too even, the surfaces are too clean, and the edges of things too sharply defined. The real world is cruddy and messy and imperfect, uneven and cracked and dusty. Computer-generated images rarely have that gritty quality, because it takes more effort to put it in than to leave it out. Reality is always more complex than its representation.
There are other reasons to simplify besides removing complexity that doesn't add fun. Most computer games have technical limitations on how realistic they can be. I once had to work with someone who insisted on putting absolutely realistic physics into a football game. The problem was that the machine we were working on didn't have the horsepower to compute his physics model in real time. The game bogged down and it wasn't much fun. We simplified the physics and suddenly the game was enjoyable again. All game programmers make these simplifications routinely, but as a designer it helps to know how they're being made and why. Simplifications made for technical reasons almost always have consequences for the gameplay, and sometimes introduce bugs or loopholes.
Another reason to simplify is to make a game more accessible. Games, especially board games, tend to be symbolic. This makes them easier to learn and to understand: chess is war reduced to black and white. Computer games often make use of the same symbolic/iconic characteristics. The first edition of the game Balance of Power, which was about geopolitics, assumed that there were only two superpowers in the world, the USA and the USSR. All the nations represented (and that, too, was simplified) were aligned in varying degrees with one of the two superpowers. This made the game immediately comprehensible and accessible, placing the player on a simple me-versus-him footing. Balance of Power was a huge hit for its time, and was even used by the U.S . State Department as a training tool in spite of its artificial divisions.
Simplification isn't always a good thing. Personally, I don't believe computer entertainment will reach its full potential until it transcends the "game" concept, the black-and-white, simplified moralities that it has borrowed from board games. Still, there's room for both in the marketplace. It's possible to have spy novels and action movies with good guys and bad guys, and rich, subtle explorations of the human heart like those of Dostoyevski and Truffaut. I believe it's possible to have rich, subtle computer entertainments too, although I don't think I'd call them games.
As you design your game, it's best not to simplify too early. You might close off valuable avenues of thought, areas of exploration, by deciding too early on that "this game won't deal with such-and-such." It's better to include such-and-such in the design and remove it later than it is to try to graft it in afterwards.
On the other hand, one of the worst mistakes an inexperienced designer can make is to assume that things can remain fluid and undefined forever. We saw a lot of this when Hollywood tried to get into the business – movie people aren't used to dealing with software engineering, so they're unaware of what havoc it causes when they try to change things late in the development process. The time to simplify is about the time that you sit down with your developers and work out a schedule. That's the point at which all the brainstorming and wild ideas need to coalesce into a single product that people will understand and can build.
Simplification isn't exactly a tool that you use; it's more of a process that you go through. It's a process that you shouldn't enter blindly. When you're trying to simplify a game design, ask yourself where the tradeoffs are: what it's getting you and what it's costing you. The more clearly you understand these decisions as you make them, the better you can explain them to your marketing and development teams.
Attention friends and fans: After five years as an audio/video producer on Madden NFL Football, I'm about to embark on a new adventure. Starting August 1st, I'll be the lead designer on the next game in the Populous series from Bullfrog Productions. I don't mind saying that I consider this the high point of my professional career to date. I have always admired Bullfrog's products immensely, and I enjoy their eclectic combination of outrageousness and innovation. I can't think of a better place to be working.
Even though I'm moving my home, my family, my career, and my cat to Britain, I won't forget my responsibilities to you, my loyal readers. The Designer's Notebook will continue to come out monthly here at Gamasutra. Thank you again for reading it.