Sledgehammer Games' critically acclaimed installment into the annual FPS franchise, Call of Duty: Advanced Warfare, contained a whole slew of improvements upon its predecessors. From the Kevin Spacey-led campaign to multiplayer's added verticality, it was largely regarded as the best entry in recent memory. Although Advanced Warfare retained most of the modes one would expect from the series, it was missing a core feature when it hit shelves one month ago, that being the wave-based "Zombies" mode. Thankfully, Sledgehammer has finally decided to lift the curtain off of their take on the 4 player co-op mode.