The graphics and sound are epic. It's crazy that you had three whole different music tracks. I really like how there's multiple phases where you gather resources in first person but then build the fort like a level editor (I just wish that there was also something to do in the third phase like maybe attacking monsters in first person). The building mechanic is super cool, I like how there are different ways to kill the enemies with traps or cannons. The only complaint I really have is that the enemies don't really demand a very complex fort. Cannon + Wall spam seem enough to get through most waves even though you can build multiple levels with ramps and stuff. Also, I encountered a strange bug after the third wave where the game went crazy (II got stuck in the transition animation between scenes but I could hear enemies destroying my fort). I think it's because I pressed enter more than once.
But overall, a really cool game!