Zombie Killin'

Also known as Zombie Killin', steam:582350, zk

Zombie Killin' is a cooperative action game that can be played locally with up to four players. In it, your team must shoot its way through an endless onslaught of zombies while at the same time individually accumulating cash and purchasing upgrades. After each game, the team is rewarded zombie coins which can be later spent to unlock new stages, options, cheats, and interesting extra modes.