Pretty cool game. I think maybe the link to the theme is a little tenuous... Maybe it would have been more fitting if the player could only see one side of the cube at a time rather than two? I think that might have been a bit better gameplay-wise too, as usually if you can see two sides you can pretty much see everything that's happening.
It's a neat idea though, I really liked the style and the level design was pretty smart! Good stuff!