Rules
In 2005 David Parlett published an analysis which splits rules into three categories:
- Operational procedures -- how to play the game. Examples: what to do when you land on a snake's head in snakes & ladders.
- Implicit rules -- rules which are implicit or subconsciously known. Examples: when you roll a number with dice, you move that many squares; a player's turn in Scrabble should not exceed 10 minutes.
- Written rules, laws & tactics -- rules which need to be stated. Examples: number of players in a football match; the penalty applied to a player for attempting an illegal move.
Jesse Schell states that the set of rules must contain a clear definition of the goal of the game. Examples include chess (capture the opponent's king), ludo (be the first to get all four counters 'home'), and Donkey Kong (get to the top of the screen).
Personally, I feel that Schell is being too simplistic here. Games such as Space Invaders & Mario Kart may have concrete short-term goals (respectively, "shoot ALL aliens" & "don't come last in the race") but they do not necessarily have clear long-term goals.
Does anybody really play Space Invaders just to accrue the highest score? Do most Mario Kart players really care about unlocking every type of vehicle or building up awards on a driving licence? I'd suggest that goals are very important, but not vitally important, within a game's design; attaching too much importance on goals can sometimes detract from the sheer fun of playing.
More to come in the final section on game mechanics, looking at skill & chance!