The demo is here:
http://www.gratuitoustankbattles.com (http://www.gratuitoustankbattles.com)
OK, a must-buy! A tower-defense game that allows attack as well as defense with a unit and map editor and creator.
Cool. I probably need to get this.
If you buy it, put the registration key, not the password, in the "Serial Code" box on the profile screen.