I want to say it's called SHIFT. It's pretty simple, short number of levels but an interesting concept. Black and White platformer, but when you hit the SHIFT key you shift into the other plane, i.e. black to white or white to black.

That sounds like Polarium for the DS.

Been playing that for almost/over 2 years now, I remember first seeing it on the I-mockery Internet board (R.I.P!!!!)
This game showed me 2 of the greatest bands ever, LDoH and Inhume.
The only weakness of the game is Regurgitate.
Fuck Regurgitate.