Very good puzzle game.
Excellent idea, well executed. Smooth play, unique idea, obviously a lot of time and effort put into it. Music and backgrounds, as said before, can be a little off-putting, but since both can be turned off no marks lost there.
Unfortunately I just couldn't see it through to the end, not because I couldn't work out the puzzles, just because it became so frustrating trying to cross out lines of squares, for example four out of a line of five, and not being able to. Not sure if I'm missing something, or there's a specific technique to it, but on level 30 where you have to try to remove partial lines often it just became too annoying to put up with any longer.
Perhaps if the squares were spaced out a little more, or there were a better register for removing partial lines of blocks, so I could perhaps draw halfway into the next block and it would only recognise blocks with a line completely through?
If this was fixed, or if someone could tell me the trick to getting it right, I'll gladly come back and finish the game, as it's one of the most clever puzzles I've seen on here in a long while.