I have it for PC; I enjoyed it, but it was really short and easy. I beat it on hard pretty much right after I beat it on normal. The whole "you can't die" aspect kind of removed all the challenge from it.
But, even with all those complaints, I did find it to be a very fun game. The gravity differences were very interesting, and some of the less conspicuous portals really messed with my mind. (walk down a hallway, turn a corner and see a six inch thick sheet of metal that you just walked out of)
It was definitely worth the 15 dollars I spent. :-)