Part of this brilliance is that the game is constantly evolving new ways with which to challenge and surprise you. In the first world, the time control is just a means of achieving near-impossible feats; fail a tricky jump and you can just rewind the game to the point before your disastrous leap. By the second world, Braid has introduced objects and mechanisms that are immune to time's reversal, producing new hazards for you to face, but also new ideas to exploit. Simple door, key and lever puzzles that would have been dull in any other game become brain-bending trials of lateral thinking. Then, in the third world, Braid ups the ante once again with a series of levels in which the passage of time is locked to your movement. Move left to right and time moves forwards, move right to left, and time flows in reverse. Suddenly the game isn't just about completing tasks, but about completing tasks in a particular, hard to handle order. Then, just when you think you've seen it all, Braid throws in a shadow of your character who repeats whatever action you performed before reversing time, then uses this mechanic as the launch-pad for a whole new series of conundrums.
To be frank, I can't remember a platform puzzle game that packs in so many exceptional moments. At times, Braid can be frustratingly difficult; you'll struggle to see the solution to a problem and spend half an hour wasting energy on increasingly more desperate theorems. But then something clicks and you'll suddenly see not just that puzzle in a whole new light, but several others that are holding you back on other levels. It's every bit as clever as Portal, which given its 2D simplicity is an impressive feat. It's also worth mentioning that the fact that you don't ever actually die means you're rarely pulled out of the game. Once you're in, you're in for the duration (or at least until somebody drags you away from the screen).
In short, it's hard to criticise Braid on gameplay terms. You might say that it does a bad job of explaining one key game mechanic which might stymie players until they work it out, but otherwise it’s pretty much faultless. For me, the only thing in question is how the game holds up as an artistic achievement. By this, I don't mean the visuals, which are beautiful hand-painted sprites and backgrounds with layers of gorgeous animation in the background. Seen in motion, the effect is always convincing and occasionally breathtaking. I certainly don't mean the music, which is haunting and hugely atmospheric. Braid is nothing if not a distinctive and impressive piece of interactive art. No. The only problem for me is that I don't find the game as emotionally engaging as many other critics (and players) have made out.