Take a look at this video of indie platformer Oliver and Spike in action. As it starts, you're probably thinking that it looks pretty nice, a comfortable modern take on 3D jumping.
Then you hit the point where he looks like he's going to fall short of a jump, and everything changes. I know that dimension-shifting itself isn't a new thing, not even in the context of games like this, but such a complete transformation in the look and handling of the world? That's some amazing stuff right there, and such world-bending will form a big part of the game's experience.
Oliver and Spike is currently in development for the PS3, 360 and Wii U, with the potential for PC and Mac ports down the line.