Simple but well executed puzzle game. The different levels work well to introduce the mechanics little by little and bringing more complexity level after level, but I think you should have gone a little bit more crazy with the level design. The most fun was when one single movement was triggering a chain, where I had to observe and anticipate what would happen, but most levels are a bit "shy".
I would say the same for the visuals actually, it works well but is quite classic too.