In Black Ops, You get FIVE and Dead Ops Arcade by completing the campaign or typing in 3ARC UNLOCK in the computer, And in World at War, You unlock Nazi Zombies (you have to on the Xbox 360,PS2 and PS3) and the map you get in World At War after beating the campaign or with cheats (PC and Mac only) is Nacht Der Untoten, Which you can get in Black Ops by getting Rezzuruction,Buy the Hardened or Prestige edition of Black Ops.
I don't know many but I know 3ARC UNLOCK will unlock all levels including five, a zombie level. And DOA unlocks an arcade version.
50 levels
9 campaign levels.
The zombie maps are not there to unlock. The downloads for the 4 DLCs including the WAW Zombie maps are as many GB as the Game is. You have to purchase the downloads and not just unlock a map. That is not even possible because they are not on the game disc
15 levels if you finish them you get a zombie map
ALL zombie maps have infinite levels with increasing difficulty as the levels go on.
unlimited
There are 65 multiple player levels to unlock
there are fifteeen
There are 15 total campaign missions.
There are 18 levels. However if you play on max difficulty, you will unlock two more levels.
You don't. The other levels are unlocked by, first for the second one complete the second campaign. For the third go to the main menu. Mash on the aim and shoot buttons, so you break free of the chair. You'll find a computer and type DOA in it to unlock dead ops arcade