Bought it today via Steam. Fifteen bucks on PSN didn't seem quite right, but ten for the PC version seemed okay--I figured it'd get better support, higher res, etc. It's my first time through Limbo and I'm around an hour in, but I find the controls fairly aggravating: The arrow keys control movement, with the "up" key controlling both climbing and jumping. Doesn't work all that well, and there's no way to change the controls or anything else for that matter. Still, really digging Limbo. I'll probably hook up my game-pad shortly.