The graphic of this game is really amazing. You are indeed a very skilled 3d Artist. The music and the sound effects are fitting too.
The mechanics themselves are interesting, but I feel like they don't really synergize together. The reloading forces you to stand still while the fireball hits you. Also the recently killed enemies still body-block you and it can be hard to get to the coin in time.
I would also pick on the balance of the towers, especially the cannon, but I too created some sort of tower defense, and I know how hard is to balance these things out. Overall, good game.