I actually really really like this, and I'm usually not one for tower defense games. I liked the controls and moving around and placing towers/fences. However, having to run over to the tower/fence buy stations threw me off. Especially since there is no time to let me know when the next wave was coming in. I'm not sure if different enemies had special abilities (maybe more health than others), but I think adding that could be cool. Some indicator to let you know when a tower is out of ammo would be a life savor haha.
Nice job!