The goal is simple; destroy alien portals before they destroy yours. Under the strict guidance of your will is a modest turret. It cannot be destroyed, but is stunned upon collision with the enemy. Firing all out is not enough to achieve victory. Even when you are winning, monsters can slip into your portal. One can soon turn into ten. Also, new portals teleport new monsters.
Page 4 of 10
1 2 3 4 5 6 7 8 9 10