Blow apart big waves of zombies using an array of guns and hired buddies to fight by your side. Purchase bigger and better guns and hire assistance with big firepower to give those hoards of zombies a good spanking, keeping them away of your territory.
You and a handful of others form the Last Line of Defense, pooling your remaining stockpile of weapons, special ammo, bunker defenses, and super-weapons to fend off the onslaught by virus infected, bloodthirsty Ravagers.
