well wasnt there a app for ipod/iphone thats just nazi zombies itself?
yes, there was, but it was just nazi zombies maps that had already been released. as much as i hate to say it, Treyarch is probably never going to release a nazi zombies only game any time soon. it was originally an easter egg, and will probably only be released with other content until it is popular enough for a stand alone release. this is what they did with portal. it was released with other content that was a safe bet to attract people to the game, and portal was more of an experiment than a game. if enough people tell Treyarch the want a nazi zombies games, it may be made.
nazi zombies is extremely popular. in world at war, zombie lobbies outweigh multiplayer by 4x. the only reason i havent sold blackops is cause of zombies. blackops itself sucks, the weapons arent balanced, there isnt enough variety for people who dont want to use overpowered assault rifles. its just a crappy game overall
