Adolf Hitler, after realizing he has no other option, decides to activate Plan Z - use the Sagarmatha relic to unleash a final, desperate attack upon the world: A legion of unstoppable, undead soldiers formed by the corpses of his country's fallen soldiers. It is up to Karl Fairburne, the US Army's most capable sniper, to find a way to defeat and eliminate the undead horde that Hitler summoned. He is helped by three other snipers hailing from the USSR and Germany.
Sniper Elite: Nazi Zombie Army is a standalone expansion of Sniper Elite V2. The gameplay is almost exactly the same as in Sniper Elite V2 - you have the same weaponry at your disposal, including many sniper rifles, machine guns, handguns and a shotgun, plus grenades, dynamite, and mines. Like the earlier games in the series, the game difficulty also alters your rifle's physics - it's fairly easy to score headshots on the easier difficulty, but higher ones force you to adjust your shot, taking into account the target's distance and your specific rifle's capabilities. You also have the capability to hold your breath and slow down time, giving you more time to hit a crucial head shot - but to do that, you have to keep your character's heartbeat steady by taking your time and not rushing through a stage.
While the earlier games in the series were more focused on having patience and strategizing your attempt at completing your mission objectives, this game ignores all that in favor of pure survival horror, with hordes of undead soldiers rushing at you. These soldiers will not die unless they are shot through the head, or destroyed via an explosion. Asides from common grunts, there are suicidal zombies who will lunge at you and blow themselves up, and enemy sniper zombies which jump from building to building to shoot at you. There are also elite soldiers at the end of each chapter which take many direct headshots to defeat.
Also new to this game is a cooperative multiplayer mode, where up to four players can fight against the hordes of zombies as they progress through the game. The amount of zombies will change depending on how many players are in the game for an additional challenge.