Curious whether Army of Two: The 40th Day's co-op "Extraction Mode" makes pre-ordering the game (thereby getting a one-month head-start with the new game mode) worthwhile? We suggest checking out the first glimpses of the co-op offering in the video above. Following in the vein of Horde Mode or Firefight, Extraction pits four players up against wave after wave of masked, gun-toting enemies as they move from checkpoint to checkpoint, attempting to escape the warzone. Teamwork is encouraged -- apparently, it's better to act as an Army of Four rather than Four Armies of One. Remember, one month after the game launches on Jan. 12, Extraction Mode will be free to download for anyone who didn't pre-order the title. This head-start may be enough to get your ire up, but can't we just be grateful they're not charging for this extra content? C'mon, we're already drowning in petitions over here.