Your game is cool, but I found it to be a bit hard to grasp. I had to play it twice to understand exactly what I was doing. However the graphics and the "music" and sound effects are what make this game shines in my opinion.
I think, it would need some more explanations as to what to do, as the first introductory screen feels a bit overwhelming. Each element probably needs to be introduced one by one.
Anyway, great work :)