There are many goals of game design, but probably the most important is the ever illusively defined “fun”. It’s hard to define what features or dynamics create a game fun, and the dynamics of this definition change for each person. Chris Crawford says fun is a bad word, and I tend to agree. However, there are some constants involved in every game, mainly, a balance between several axis’s of design:
Strategy vs. Reactionary
Strategic games often require complex thought over the consequences of a given move or choice. They usually don’t force the user to form decisions in highly limited amount of time, but instead the user is asked to weigh the options of all available moves while forming some type of long-term strategy to accomplish their goal.
Reactionary games rely on users training themselves to certain stimulus, and being able to react to that stimulus under tight time pressure.
Depth vs. Breadth
This is a measure between how much there is to do in a single game element, or the depth of a game system, and how many elements are in the game, or the breadth of the game’s systems.
Games which feature deep systems can interest users in a single system for a much longer time, but if the user grows weary of playing with that system, they often become wary of the game as a whole.
Games which feature many shallower systems often give the users options. While each of these systems may be less satisfying that a single deep system, the variety in game play attracts a potentially wider audience, and allows users to spend more time with the game as a whole, since as they become bored with one system, there are other systems to play with. Any system which intersects in some way with another system will often create emergent or tangential effects, which often further widen the possibility space.
Skill vs. Luck
People are fascinated by the concept of luck. But while people are fascinated by facing the odds, they often want some measure of skill involved for the act to seem gratifying. Even when playing purely luck based systems, the human psyche tends to place skill based beliefs onto the system. This is why people often develop superstitions and systems to playing purely luck based games – they want to believe there is more to it than luck; that blowing on the dice will cause them to roll a seven, or an article of clothing will cause the cards to be dealt in their favor.
Purely skill based games are popular with those with a competitive edge. However, with any purely skill based ability, a small number of people will rise above the average skill level by such an amount that very few people will ever be able to compete with them.
Most mainstream games combine skill and luck, and generally speaking, the most popular social games involve a large amount of luck with a minor amount of skill. This acts as a great equalizer, making it possible for anyone to win.
Examples of pure luck based games: Slot Machines, Craps
Examples of Luck biased games: Backgammon, Uno
Examples of Skill biased games: Tetris, Poker
Examples of pure Skill based games: Street Fighter II, Chess
As a game system is created, it’s important to think about how it fits into the above axis’s, and consider other successful games which lie in the same space. This will often lead to a clearer understanding of both what will make that system successful, and what audience it will appeal to. Of course, I still believe the first audience should always be yourself.