This was awesome! As others have said, the graphics were very cool! Made me feel like I was playing this in my own notebook while at school or something!
I think if each trap had a little description that gave some detail of how it worked when you hovered over it, that would have helped a lot with knowing what I setting down. I got the hang of it after a few rounds, but it took me a bit to realize that the ambushes were ranged, and didn't expire immediately like the bear traps or the hidden pits.
But I still had a blast with this one! I could definitely see this turning into a full on wave/tower defense with this art style! Great job!