Tower defenses have become such a saturated with games genre, but surprisingly, you could make a very original concept of how to make one with a twist :0
Also, I think your art style is amazing, and it's such an awesome job for under 48 hours. Although, I didn't like how all the colors mixed together (I'm not saying I didn't like it, I just mean that I think you can choose even a better palette :D )
If you consider finishing the game, then good luck to you, because it really has a lot of potential for being a fresh strategy game.