I happened to stumble upon this while I was looking through some Game Jam 9 stuff. It really got me thinking how cool it could be as a number of different genres. It could fit a puzzle game in that you discover the Shadow Side at the same time the Shadow Side discovers you and you maybe have to find a way to stop it, or possibly end up switching places. It could work as a mini-RPG or platformer or even a simulator game, but puzzle would be the ideal.
It's a really cool little concept that you've got going in this picture and I hope a game based on this (I believe somebody in the game jam is trying it) really turns out well. Nice job!