Love it.
I love this game. It's certainly a classic tower defense game.
I like how this gets you to think of a strategy to implement rather than put down whatever you can afford or put down lots of random turrets. Certainly something that gets your brain moving.
Although the graphics leave something to be desired, I rather like the simplistic look. As I'd rather have something that looks simple and plays great. Than something that looks amazing and plays badly.
10/10.