Honestly, there aren't many games that allow you to play a villain without severe consequences. Most games force you into being the hero or just have the story set as you playing the hero. Personally I want a game where you play the bad guy, but don't really know it until too far in. Maybe a game about war where the line is very gray morally and nobody is really sure who's the good guys or bad guys. Maybe an RPG where you are just doing quests that you're given and only through scattered notes and lore do you really find out who you're working for and what you've done. I think it's not really an explored concept. Maybe it's just too hard to properly execute.
