This is definitely one of very best tower defense games on Newgrounds.com
The only minor issues are that the tutorial could be a little clearer and the campaign is rather short.
But you can continue with random maps.
I have always been a lover of RTS games, i got started when I played Army Men: RTS on the PS2, and since then I've loved RTS games. This is a wonderful example of a free to play RTS game.
I never could figure out how to collect resources, the tutorial was pretty unclear about that. Otherwise, this game is pretty unappealing and a complete letdown, whether it was due to the graphics, the music, or the gameplay itself.
tild (~) key speeds up the game.
This game is wonderful. As long as you don't give to many commands to your survivors at once, it is a very smooth game. I have spent hours on this game and still come back to play it.