I'm really digging the audio, wish I could do that! Could benefit a great deal from showing which color is destroyed by which button, was stuck for a couple minutes in level two because when you fail just once when the rocket comes in you die :(
If you don't want to show which button does what, I think it would be nice to give the player more time to learn them. The yellow building completely threw me of as well, since I thought it was the same as blue but for the other button. I can see where this is going once you know the controls in and out, and is probably a lot of fun once you get there, but you need to give the player a chance to get there ;) Looking forward to the post-compo version!