I love the art style! I'm also impressed that through visuals alone, you're able to effectively convey exactly how to play the game. Furthermore, I enjoy the gameplay too, not too hard nor too easy. The only thing I can nitpick is the fact that the game doesn't fill the window.
It's a little short now, but I see that you have a lot planned. I'm sure this game will grow to become something really amazing (*^▽^*) Not that it isn't already pretty rad