ok so if anybody is familiar with world at war zombies on the pc you can create your own zombies map once you download the tools to do so , or you can download other players custom built maps and you can also use guns from any other call of duty, create your own perks you basically can make everything . You can even create your on mysterybox and choose what guns will be in it and i would really like to see it happened in all the next call of duty Treyarch games many people love it and people from syndicate, ngtzombies, and dumb and dumber and all of they have youtube channels check them out as well. And this should be the only zombies in the game.
here's a few links to go check out their really good
Dumb and Dumber