Let me begin by saying that I believe I have done everything that one can do in Braid. I have collected all of the puzzle pieces. I've gotten the "Closure" achievement, and I have collect every last "extra". There may still be unfound stuff to do, but as of now, I've done everything. I have spent roughly 10 -12 hours on Braid. And I enjoyed every second of it.
Graphics: Braid is done in an art style not yet seen on an Xbox Live Arcade game. Braid was designed to be beautiful. A hand painted water color art style creates an atmosphere that you really would just like to lose yourself in. And there's a good chance that you will. The animations are simple, but that fact really just adds to the simple nature of this wonderful game.
Sound: Another of Braids strong suits is its choice in music. All of the songs chosen fit their respective levels perfectly. I believe that there are only 10 or so songs, but they never feel over used, and they never feel as though they don't fit. The sound effects are simple as well, with a simple boing when jumping on a rabbit, and a pop when a flaming ball is shot from a cannon. Speaking of rabbits, watch out, because they have quite the growl... and teeth.
Story: Braids story is one that is meant to be thought about. Its ambiguity lends itself well to interpretation. A quick search through any internet forum that is about Braid will show many interpretations, ranging from the literal "Man rescues princess" to detailed looks at the story books, and they're allusions to the nuclear bombs. While the in game story didn't quite grab me, I still found it to be interesting. Many will believe that it is pretentious, but I say that just because the story is open to interpretation, and is perhaps at times hard to understand, that does not mean that the story is pretentious.
Game play: Game play is where Braid is truly unique. We have all seen the rewind feature of Braid before. In Prince of Persia: The Sands of Time most prominently, and in Timeshift as well. And World 5's time element, which allows you to make a copy of yourself by rewinding, can be seen in the online game Chronotron. Even slowing down time in World 6, can be seen in games such as Max Payne or the Matrix. But none of the time elements actually feel as though they are being used in a gimmicky way. Each puzzle has a reason, there are no duplicates. You will see levels that look exactly the same in places as past levels, but due to the new use of time mechanics, they don't ever feel as though they shouldn't have been used twice. I haven't even mentioned World 4, which is really something that, as far as I know, has never been done before. As you move to the right, time will move forward. And as you move to the left, time will move back with you. Braid doesn't actually bring many new things to the table, but what it does bring to the table, new or not, is used intelligently. And as a final note, the final level will be one moment that sticks with me for the rest of my life.
In conclusion: Braid has been critically lauded. But, it has turned many people off of it, due to the price tag of 1200 points, and length. Like Portal, Braid is perfect in its length. It doesn't over stay its welcome, or present useless clones of earlier puzzles. Whether you enjoy the story or just the game play. Or even just the atmosphere. Braid is worth it. If you are one of the people on the fence, I recommend you purchase Braid. There are speed runs, which I haven't even given that much of a try, that will add upwards of 2 hours at least to the game.
I have played through Braid twice so far, in order to find one of the much coveted "extras" that I mentioned earlier, and I had just as much fun the second time as I did the first time. I don't quite understand why, because by all accounts, it should have just been a chore. But it wasn't, I found myself smiling and enjoying every minute of it. And I think you will too.
No game is perfect. And there will be people who disagree with me. But I am going to give Braid a 10. I have seen people give games like Madden and Halo a 10 (not that I have anything against Madden or Halo), and I feel Braid deserves the title more. It approaches perfection, and offers so much more in the way of innovation. If we as gamers ever want our medium to be taken seriously, we have to support games that are more than just sports or shooters. We have to support games that are art.
Braid is art.