Call of Duty: Black Ops – Zombies is a spin-off game of the Call of Duty series' Zombies mode and the sequel to Call of Duty: World at War – Zombies. Adapted from the best-selling console hit and built specifically for tablets and smartphones the game allows up to four-player multiplayer, and, as a new addition to both platforms, voice chat. It also features ranks based on Experience Points. It includes the maps Kino der Toten, Ascension, and Call of the Dead: Director's Cut as well as the unlockable Dead Ops Arcade.