Nice concept, but...
The game was ruined by VERY poor controls. Playing as the UFO, it was virtually impossible to position it to where I could shoot the asteroids, as it would conveniently slide over the exact spot I needed it to stop at.
Muncher wasn't any better as I could only ever get him to move while in the air, and even then it was difficult getting him to not go from one side of the screen to the other. His jump height also seemed to vary, and the fact that he crushed buildings with every landing didn't help either.
The easiest one to play with was, ironically the hardest monster, Polycylop. He would actually move and he had a nifty jump scheme, and his super weapon wasdefinitely the msot helpful of the three. However, like the muncher, he crushes buildings when he lands, making gameplay a bit more difficult than it should be.
Good idea, like I said. but the only monster that actually pulled it off was the turtle. So the game was completely ruined for me by bad controls.