Defend against the robo-bugs that are trying to take over your base. Unlock and upgrade new areas and special weapons. Collect enough exp points to get more powerful weapons.
The aliens are back to snack on farmer brains. This time they are filled with ACID BLOOD! Look out, the acid will harm your defenses. Strategically place the crop circles to make the maze then set up your defenses and blast the aliens back to outer space.
Build towers and survive through 51 hardcore waves of aliens that heal themselves, haste other enemies, split into more enemies and freeze your towers.
Monsters must protect San Francisco or even the world from these evil aliens. Place your monsters around the map to defeat the incoming waves of aliens.
