Every environmental cycle must introduce a new point of interest, unless the absence of that interest is part of the game’s object.

An environmental cycle is defined as a complete refresh of the player’s surroundings, be it one screen (in a 2D side-scroller) or the area between here and the middle distance (in a 3D game). The specific measurement differs from game to game according to its pacing, format, and spatial sense.

A point of interest is defined as a new concept, or a significant elaboration on a known concept. The concepts need not all be profound; they need only expand the player’s perspective on the game’s object or method.