Really nice little puzzle game. The mechanism is simple and effective and the levels are pretty good. Hopefully you'll continue to develop this game. A few suggestions, I couldn't find a way to restart a level when I got it wrong so I had to restart the game. Having some kind of win reward would be nice, even you a "You solved it" message would work. Maybe make the first few levels easier so they act almost as tutorial levels. Great work though - keep going!