6. Dead Nation
A game in the vein of Metal Slug, where absolute maniacal carnage is the main lure. Only available through PSN, Dead Nation excels in the whole PEWPEWPEW style of gaming but a surprising amount of teamwork and strategy is essential to a playthrough, whether that's through modding your weapons and armour or coming up with a good way of getting through a level while collecting the most loot. As far as enemy variety goes, this game has your standard shuffle-zombies on top of 'Screamers' that call in reinforcements, biological experiments with knives for hands, and worst of all is the acid spitters. No matter how many times I've played this, whenever I've had to abandon my smash-n-grab to go for the safehouse I am always amazed at how fast things went from manageable to chaotic - exactly how a zombie apocalypse would be.