Really fun spin on the tower defence genre. I would definitely play the hell out of a more polished version of this. One gripe I had was the numbers to the right were a bit close to the creatures you could pick to place, and the numbers actually overlapped the starting text for me. That and making it easier to see how much each creature would cost in each zone and I would've played it a lot longer than I did.
Great music, fit the tone well.