So I bought Braid with my 20% discount on Impulse. While I enjoyed it, I'm glad I didn't pay more.
The gameplay itself is pretty fun, and the time manipulation was really interesting. What the game needed was some more levels. It is really short. I want to play more but there is no more to play, and I started playing...what, yesterday?
The story stuff is way overblown. There was a neat twist at the end (that I won't spoil) that uses the time manipulation itself to tell a story which I thought was great, but other than that it all felt so pretentious and unrewarding. You can leave stories up to interpretation, but Braid seems to be so utterly vague that you have no idea whats actually going on. Thats not "powerful", its just blowing smoke.
If you can play it for cheap, go for it. Its fun, for the gameplay. Just don't listen to the reviews that make a big deal out of the story. Its a big "games are art" wankfest.