If you want to see what a four-player co-op experience in Army of Two is like when Army of Two II: The 40th Day is released on January 12th next year, make sure you pre-order. Electronic Arts is restricting the Extraction mode (think: Firefight from Halo 3: ODST, Horde from Gears of War 2) for an entire month to pre-order players only.
"The first multiplayer mode, and in my opinion the most exciting, is Extraction," said Eric Chartrand in a developer diary on the game's official web site. "Extraction is a new game mode that was devised as a bonus for pre-orders, giving gamers who preorder a month of exclusive access."
My prediction: the reaction to this move will be negative. I've contacted Electronic Arts for more details about the pre-order program. As soon as I hear back, I'll let you know.