This is awesome, I'm happy to see a tower defense game -- one of my favorite genres! I really enjoyed the game. You executed the shop, camera angle, and different items well. The game feels strong for what it has. I also like how you can place the towers and other objects pretty much anywhere on the map, not just in pre-chosen positions like in most tower defense games. That alone makes the game stick out in a unique way to me.
Great job!
-AJ