From start to finish Zombie Army 4: Dead War is the first game in the series we have completedtwice! Why multiple playthroughs you ask, well, lets just say that with so many empowering features being thrown at the player, Zombie Army 4: Dead War is one of the best Zombie killing action games we have played in quite a while.
Source: N4G PC Zombie Army 4: Dead War Review The Best Co-op Zombie Shooter in Years – Game Insider