TWA was released this week on PSN for PS3 and Vita (crossplay enabled).
I spoke to the game's creator Mike Bithell via Twitter earlier, looks like a 360 version is not out of the question.
Which means to me there is no (paid for) timed exclusivity in place (or he otherwise would not have mentioned it). That Bithell went with Sony because they showed interest and got the deal in place. This a good sign for Sony.
Besides all that though, give Thomas Was Alone a try, it's a great game on Steam or on PSN.