I'm surprised a number have people have mentioned the "two door" thing (to confirm, yes, there is nothing "random" about it, and if you do screw up, it takes all of 10 seconds to walk back to the door and reset the room), but no one's mentioned the "lazy repeated design" thing.
There was absolutely nothing lazy about this -- in every case, there is some new and interesting puzzle to solve, even if the elements appear to be arranged the same way to first glance. "Hunt" shows up twice, for instance, but the mechanics of the two worlds they appear in make them totally different when it comes to actually solving it. "Phase" appears twice, but the second time, half of the platforms have disappeared, forcing you to use your time manipulation powers in a new way. This is the first time I've really strongly felt Yahtzee was completely off-base with a review.
As for the story/gameplay divide, I don't agree with him, but I don't disagree with him. The writing is pretentious, and if you're waiting for a clear explanation, it's never going to come. The story is not required for the gameplay, but each world tied its unique gameplay mechanic to the emotional issues of the protagonist; I thought that was really neat. World 5's gameplay gimmick/emotional setting always gets to me. I think Joe Blow tried to do something new here, and it's not going to work for everyone. To me, it worked, and a number of people I've shown it to have confessed that it touched upon something personal to their lives regarding relationships and regret.
As for everyone left wondering what Braid is about: it's a puzzle platformer with a little bit of hop-and-bop, it will mess with your understanding of time worse than Portal messed with your sense of space, it's absolutely gorgeous and if you enjoy using your brain you should drop the $15 on it without hesitation.