I'm curious how you see this as differing from games where the player/protagonist changes alignment and therefore story arc based on their actions. Specifically thinking of Fable and Black and White--both by Peter Molyneux--and probably Skyrim and it's "natural" skill learning system. (Note: I never finished either of the Molyneux games, and haven't played Skyrim yet.) Or do those Good/Evil path games simply railroad players into two alternate versions of a narrative?