Game mechanics are constructs of rules intended to produce an enjoyable game or gameplay. All games use mechanics; however, theories and styles differ as to their ultimate importance to the game. In general, the process and study of game design are efforts to come up with game mechanics that allow for people playing a game to have a fun and engaging experience.
The interaction of various game mechanics in a game determine the complexity and level of player interaction in the game, and in conjunction with the game's environment and resources determines game balance. Some forms of game mechanics have been used in games for centuries, while others are relatively new, having been invented within the past decade.
Complexity in game mechanics should not be confused with depth or even realism. Go is perhaps one of the simplest of all games, yet exhibits extraordinary depth of play. Most computer or video games feature mechanics that are technically complex (when expressed in terms of making a human do all the calculations involved) even in relatively simple designs.
In general, commercial video games have gone from simple designs (such as Asteroids) to extremely complex ones (such as Tom Clancy's Splinter Cell) as processing power has increased. In contrast, casual games have generally featured a return to simple, puzzle-like designs, though some are getting more complex. In physical games, differences generally come down to style, and are somewhat determined by intended marke
Nadya Direkova SXSWi Talk on Game Mechanics and their Design Patterns.