Duality.

Duality is a game where you control two opposites.
When one is idle, it creates a field of colour opposite to itself, which the other character can walk through.

This simple concept can be used in complex ways, as you figure out how to get both parties to their respective flags.


The menu is possibly the slickest I've ever seen, and levels are grabbed from a server, meaning there will often be new levels to enjoy.
There is also an integrated level editor for you to try yourself, and it's very slick and easy to use.

To be honest, I wouldn't be surprised to see this win.