Well Done.
Nice job. I thoroughly enjoyed the game. The puzzles toward the end were surprisingly difficult - it was awesome when I finally cracked them.
I'm fairly certain that the solutions I have for levels 21, 24, 25, 26, 27, and 29 (especially 25, 27, and 29) are pretty unorthodox. I'd love to make a youtube video showing the ways I did them, and look at other ways, including the "official" method. But I don't want to be the asshole who ruins how to solve the puzzles for other people. Part of the fact that makes this game so fun is that there's no walkthrough - though I'm sure some people could appeciate some hints here and there.
Reason why I gave it 9/10 is for two reasons - one is that there seems to be a small bug where the avatar keeps walking even if you have no keys pressed when you land on patch of ground that's normally a wall but is only partly illuminated. This happens some of the time, but I'd surprised if this didn't happen to you if you played through the game the entire way. I'm sure you'll encounter it a few times, and it's a bit irritating to start the level over again when the avatar kept running and you didn't want it to.
Second reason is because it'd be nice if you could go back to the menu screen once you're in the game, so you could select another level.
Other than that, fantastic game. Good job. (Heck, I created an account just so I could write a review, that's how good this game is).