Killing zombies. The concept has largely been driven into the ground. Smaller developers, like Kuju’s Doublesix studio, have taken advantage of this reliable ubiquity, knowing they can have a bit of fun with the mechanics without worrying about marketability. The team previously released Burn, Zombie, Burn! on PSN, but All Zombies Must Die! takes the formula, expands on the co-op options and puts in an upgrade system to combat the monotony of taking out zombie waves.