Good Game
Well programmed, Graphics COULD have been better, but that would have slowed down the game. You should add more stuff, by the end of the game it would be nice if maxing out one thing should be an accomplishment, by level 14 I was fully upgraded.
2 bugs in buy screen:
1) AA tower says it has a max of 6, but after 5 it was greyed out and I couldn't buy any more
2) Your Turrets firing speed says a max of 23, but once I got to 22 the button stayed lit, but nothing happened when I clicked on it.
I would really like to know how to get to level 21 and such on the high scores, with my fully upgraded base besides those two bugs, at level 17 it was impossible to kill the infantry guys with the rockets, my gun would point at them but more people would spawn than my gun could kill. So they just picked away at my health since they were invincible behind the meat shield.