Army of Two: The 40th Day starts pretty much where it ends: Two players (or a player plus the computer) assume control of Salem and Rios, a pair of mercenaries who appear to trigger and then wind up in the cross-hairs of a massive terrorist assault on Shanghai. Cooperation is the theme of almost all player actions, from the way you will shoot through a firefight to the moral decisions you need to make throughout the game. You're pinned down by enemy fire... you want to ask the little boy hiding on the sidelines to grab a sniper rifle and help you out? You sure? What does your friend think?