I couldn't get over the fact that the player's hitbox and camera were slightly offset from their point of rotation, causing money collection and actually lining up to select/place turrets a lot more of a hassle than it should have been. When I found a tornado powerup to pull in all the money I couldn't spend it in time before I died because I had trouble lining up placements.
Other than that, great game! I really liked the cost balance with price increases and having 3 archetypal towers, and the 3d first person tower defense is hard to pull off. The game felt like it was just one constant wave due to there not being many breaks so I felt a bit bogged down. The idea of having special drops is cool, and that's something you could expand upon to improve your game. I would also add a few more tower and enemy types to spice up the gameplay. The idea that enemies would pathfind from all directions to the center through a maze is also rarely explored but could be good.
If there was a potential category you would earn an easy recieve 5 stars there.