I recently got a glimpse at the latest level of "Call of Duty: Black Ops" which, if you'll recall, has a shotgun that shoots fire. After checking out the demo, I had a chance to speak with Mark Lamia, the studio head of Treyarch, to discuss some of the currently-unknown elements of the game. While he wasn't super descriptive, he was able to shed some light on how co-op will work. Specifically that it'll be totally separate from the main campaign, which will remain a strictly solo experience.
Lamia broke the different modes of the game down like this:
"Single-player is the epic, cinematic, seat-of-your-pants thrill ride that you star in. Then there's multiplayer, when you want to play competitive with your friends and really chisel and hone your skills and do that addictive experience. And then co-op is for when you want to have a blast with your friends, just sitting on the couch and having an awesome co-op experience. We're crafting unique co-op modes around that experience, but it is different than what people think."
I asked him whether co-op would be similar to Spec Ops mode in "Modern Warfare 2" (beyond allowing four players instead of just two). Lamia confirmed that "it is different than Spec Ops," but wouldn't go further than that.
You'll note that he did say co-op modes, plural. You may recall Treyarch's last title, "Call of Duty: World at War," which featured co-op throughout the campaign as well as the enormously popular bonus co-op mode involving Nazi zombies. Can we expect Commie zombies for the Vietnam era? Zommies? Again, Lamia won't say, but he did stress that the co-op modes will be unique and "awesome."