I just beat the game. Very challenging. Very simple. Great job. I'm thinking about writing a bog post about a particular property that exists that aids in solving its challenges. This is mostly a comment in response to urmelhelble's comment about the game mostly being trial and error. There's definitely a deep reading/algorithm to the game.
I had issues with the controls at first. But a bit of practice and they were very reliable and more engaging than I find in most puzzle games.
The bombs helped simplify things compared to the levels that came just before the bomb levels. I like the game. Beat it in about 2 sittings.