Prey is one of the awesomest games out for the 360. I love it! I love the multiplayer as well, tho there usually isn't a lot of people online playing it and it's a bit laggy.
I reluctantly picked this one up, and now I'm glad I did. I wasn't sure about the whole walking on the ceiling thing, but it isn't that disorienting once you get used to it. You actually take advantage of it sometimes. I fell in love with the innovative rejuvenation aspect - it's quick, so you don't lose tension or momentum. I found myself quickly immersed in the story, and didn't want to come out. Once I reached the end, I immediately played through again. Online could use some work, but I highly recommend this game. 9 out of 10