The existence of a "Realistic" difficulty mode for Call of Duty: Black Ops III was recently discovered by the game's achievement/trophy listings. Now, Treyarch has provided more details on how this uber-challenging mode works. Producer Jason Blundell tells XboxAchievements, “[In Realistic] you have one point of life, so if you're shot once, you're dead. It completely changes the way you play the game."

　　He went on to say that surviving in Black Ops III's four-player co-op campaign will require the coordinated effort of all soldiers. And patience. Lots and lots of patience, it seems.

　　"You all have to survive as a group," he explained. "You end up respecting the level in a completely different way, and once gunfire opens up, everyone just drops to the ground, because if any one bullet hits you or a grenade goes off near you, you're dead."

　　Past Call of Duty games have featured Recruit, Regular, Hardened, and Veteran difficulty settings.

　　If you're playing Black Ops III's co-op campaign with computer characters instead of human friends, you may be happy to learn that the game's AI has been completely rewritten to "make independent decisions," Blundell explained. He added: "We have more types of AI than we've ever had before."

　　For lots more on Black Ops III's campaign mode, check out GameSpot's recent preview.

　　Black Ops III launches on November 6 for all platforms. The last-generation versions of the shooter do not have a campaign mode, a point that will be made clear on the game's box. In other news, a Treyarch producer apologized for a recent Black Ops III marketing campaign involving a fake terrorist attack.

　　Activision also has released stunning new trailer for Black Ops III's zombies mode, Shadows of Evil, showing off the virtual versions of actors such as Jeff Goldblum, Ron Perlman, Heather Graham, and Neal McDonough.