A good idea, and an interesting take on the theme (that works on a couple levels too)! The gameplay is a little hard to wrap your head around-- it's hard to picture how the mechanics are going to play out. That being said I think that could be fixed with a bit of adjustment in the future.
I really liked the design of all of the creatures!
I know the audio is a bunch of assets, but in a game like this I want to boogie woogie! I would consider teaming up with a composer next time around (: