In addition to the already extensive slate of gameplay modes present in the original Left 4 Dead, Valve is adding two more for part deux.
First up is "Savenge," which pits players in divided teams of 4. In a race against time, Survivors must fend off Infected whilst collecting gas cans to refuel a generator located in each map. Each time the generator is filled with gas, time is added to the clock.
Another mode not detailed by Valve but spotted by 1UP is the aptly dubbed "Realism." If you were one of the few that trekked through Expert on the original without breaking a sweat, this mode is for you. Valve's Chet Faliszek says it is specifically tailored for the super hardcore, which likely equates to throwing your controller at the wall type frustration for us normal folk. Nice to have the option, though.
Left 4 Dead 2 is due out November 17 on PC and Xbox 360.