Mode (videogame design)

Game mechanics are constructs of or methods designed for interaction with the game state, thus providing 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, or ludology, are efforts to come up with game mechanics that allow for people playing a game to have an engaging, but not necessarily fun, experience.

The interaction of various game mechanics in a game determines the complexity and level of player interaction in the game, and in conjunction with the game's environment and resources determine 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 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 (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 Space Invaders and Asteroids) to extremely complex ones (such as Gran Turismo 5 and Crysis 2) 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 market.

...
Wikipedia