Multi-genre video games
Multi-genre video games are those video games which use multiple vastly-different play mechanics throughout the game. For example, in The Adventures of Bayou Billy, play changes between a beat 'em up, a driving game, and a rail shooter across various levels. Since most video games employ aspects of various genres and mechanics, it's often difficult to decide which game should be considered "multi-genre" and which should not.
These are multi-genre video games which are important to me, for a complete list, see the category.