Black Ops: 2 Zombies is personally my favorite, out of all the others. Obviously, Black Ops: 1 Zombies was bad-ass too, but Black Ops: 2 really gets more detailed. It's ever-so-slightly easier, the maps are different, and all of the maps go into the story of the Apocalypse. Oh, and there was a whole new arsenal of guns, too. Black Ops: 2 is probably my favorite game in the entire Call of Duty series, tbh
