Fun, but short
Very well made, and the difficulty progression was excellent, as far as it went. Still, it felt like I had only just left the tutorial levels when the game was over. Levels 14 and 15 were tough for about 10 minutes each until I figured out what I was missing... and then the whole thing was done. I realize there are user-created levels on your website, but you shouldn't rely too much on user-created content. I could see this being one of the most excellent puzzle games on the internet, if it had about 50 to 60 included levels.
4/5, (and faved anyway)