This is a great tower defence game! I really like the intro flyby of the enemy path, and the fixed perspectives in each of the zones is quite novel. It's clear that there was a lot of care put into the background decorations (the holes in the wall in zone 2 are a nice touch!). The gameplay felt balanced, though I think that the first few waves should be a little bit easier; I lost a bunch of lives to the fast skeletons while I was learning how each tower worked. Overall, it's an excellent submission!