AusGamers recently spoke with Treyarch's Mark Lamia about Call of Duty: Black Ops II.
"Yeah, that’s a good question. Our co-op mode, at Treyarch, is zombies. We are putting everything we’ve got into that. If you’re a zombies fan, this is by far the most ambitious zombie initiative -- it’s its own game. It has a world, characters, there are new game-modes we’re bringing to the table. We moved it to the multiplayer engine, which allows us or affords us all new kinds of opportunities.
Think about what we’re able to do in multiplayer in terms of the sort of extended abilities you get inside that engine. If you can think about all the different kinds of things you can do in multiplayer, you might be able to think about some of the new things we can bring to a zombies mode in that technology.
Strikeforce mode. Strikeforce mode is part of the campaingn. It is a part of the campaign that affects the branching storylines that you get inside the campaign..."