Best Challenge $15 can buy!
I have heard some complaints concerning the cost of this DLC title, coming in at 1,200 MS points (about $15 USD) but to those complainers i ask this: How much entertainment does $15 get you these days? That is one evening movie ticket and a medium soda (two hours.) It is half the cost of your average Theme Park ticket price (if you could purchase half tickets and only stay for five or six hours out of a day.)
My point is your first play through in Braid is sure to bring you at least four hours of challenge while you rewind time over and over trying to figure out just how you're going to get that last piece in the room.
Once you beat it, if you still crave more, they unlock Speed Runs for you and you can get your top times posted and ranked on leader boards.
If you like puzzle games, this game is a must buy. If you have XBLA and nothing to do for the next hour, DL the demo. i bet you end up unlocking the full game.