Another of those "facepalm Why didn't I think of it myself?" games. Shift is a very standard platformer in black and white, if you don't count a very simple and unique twist: Press the key "shift" and the level turns 180 degrees and you end up on tile you were standing, but you're flipped 180 degrees to, and have the opposite colour. This makes for some very crafty level design, where you can both shift and hit certain icons to toy with gravity. There are also some keys which change the levels' structure, making up for even more mayhem!
The theme of the game reminds of Portal (i.e. you're a guinea pig in a test lab and you're being monitored constantly and in every room), but I'm sure I played this before Portal was shipped (and in any case, don't think Narbacular Dr.... erm, Portal, wasn't influenced by other games ;)).
Nuff said, go give it a spin if you haven't already, I'm pretty sure you'll like it