Uploaded my paper from the Computer Games and Digital Cultures conference in Finland, June 2002: The Open and the Closed: Games of Emergence and Games of Progression.
It describes a pretty basic distinction between “progression” games where the player faces a series of challenges with predefined solutions (adventure games, mostly) and “emergence” games where the rules of the game interact to create variation. The description of emergence is much more elaborate in the dissertation, by the way.