FUNDAMENTALS OF GAME DESIGN, SECOND EDITION
Hiding the Rules
Unlike conventional games, video games do not require written rules. The game still has rules, but the machine implements and enforces them for the players. The players do not need to even know exactly what the rules are, although they do need to be told how to play. In most video games, the computer sets the boundary of the magic circle because player actions are meaningful in the game only if the machine can detect them with its input devices. The computer also determines when the player reaches the goal. It adjudicates victory and defeat if those concepts are programmed into the game.
This means players no longer have to think about the game as a game. A player contemplating an action can simply try it, without having to read the rules to see whether the game permits it. This lets players become much more deeply immersed in the game, to see it not as a temporary artificial environment with arbitrary rules, but as an alternate universe of which the player is a part.
Hiding the rules has one big disadvantage. If the players don't know the rules, they don't know how to optimize their choices. They can learn the rules only by playing the game. This is a reasonable design technique provided that the game includes hints about how to play it and what to expect. However, some video games force
the player to learn by trial and error, which can make the game extremely frustrating. Many people deeply dislike having to learn by trial and error, and requiring a player to do so limits the market for that game to those players who are able to tolerate the frustration.
Provide adequate clues that enable players to deduce the correct resolution to a problem. Avoid creating challenges that they can surmount only by trial and error. (Challenges that require physical skill and that may be overcome with practice are an exception.)
In conventional games that don't use a timer, either the players or an independent referee sets the pace of the game—the rate at which the events required by the rules take place. In effect, it is up to the players to make the game go. In video games, the computer sets the pace and makes the game go. Unless specifically waiting for the player's input, the computer keeps the game moving forward at whatever pace the designer has set. This allows us to design fast and furious games that constantly throw enemies or other challenges at the players, or to design slow and deliberative games in which the players can stop to think for as long as they want. Games can also modulate the pace, giving players a rest between periods of intense activity.