Hotline Miami (retro pixel, 80 vibe, super violent)
Bastion (hand drawn, colorfull, also look at their upcoming Transistor)
Atom Zombie Smasher (crazy zombies management crisis with a twist. Actually, severals twists... No, in fact, so many twist that just saying no word can make justice at how good this game is)
Osmos : elegent and simple action/reaction based concept of... stars or bacteria. You choose. Very relaxing to look and play
Splice : chromosone puzzle with smoooooooth colors. So relaxing to look at.
Botalinicula : sort of point and click style adventure about tiny bugs on a giant threes. Crazy art style and cute sounds.