Dang it, you suck
I am in the middle of developping a similar game. Now I have to make it better than this. I hate you.
Just kidding, you did a pretty good job. Honestly, though, I don't understand something here. It won't let me build more turrets even though I have a power plant, and there's no possible way to get through the second wave without more than what I built. And isn't there any way to upgrade those?