To unlock a map, the player must survive at least three minutes in the previous map. When the player first unlocks the mode, they will begin with Withstand only, and other maps are progressively unlocked. Endure, the final map, is in a war-torn Middle-Eastern town.Fallen pillars, gates, and a car are all available for the player's cover.
There are several large supply cases for the player to take cover. There is debris all around the apartment for the player to take cover behind. Doing the former only temporarily unlocks it, while doing the latter unlocks it permanently. It is only unlocked if the player either uses a cheat code, or beats the campaign on Hardened difficulty.
