Given publisher EA's reputation for producing relatively innocuous games with mass-market appeal, it's weird to see them tackle something as overtly political as Army of Two. Part ultraviolent shooter, part troubling polemic on the US military's increasing reliance on mercenaries - sorry, "private military companies" - Army of Two envisions a near future in which powerful PMCs scheme to keep the world in a state of constant (and extremely profitable) war. And you're working for them.
As one half of mercenary duo Salem and Rios, it's your job to stomp into war-torn regions and pull jobs that are too dangerous (or too politically touchy) for regular soldiers to attempt. In one of the missions we saw, for instance, the two are contracted to attack a government motorcade in North Korea, which they'll do by rocketing a bridge to pieces as the cars cross over it.
Once the attack was completed, however, Salem and Rios get a call that there's a price on their heads - apparently, their "target" was in fact a US congressman (or so the news reports say), meaning they were set up. How that'll tie into the larger plot has yet to be seen, though, as the action doesn't stay tied to North Korea - the pair's missions also take them to Iraq and (presumably) other hot zones, all in the name of blowing shit up and making bank. Eventually, though, as the two learn more about their employers and what it is they're trying to accomplish, they'll be forced to ask themselves if it's all really worth it.
That's the bulk of what we know about the plot at this point. The gameplay, meanwhile, looks to be surprisingly deep; if you try going it alone, it's standard third-person shooter stuff (although you can crouch behind cover and blind-fire over the top, which is rare), but you're not meant to go it alone. Ever. Rather than a gimmick or a hindrance, the cooperative-partner dynamic is so fundamentally tied to the gameplay that even Gears of War's impressive co-op looks simple by comparison. It doesn't really matter which mercenary you pick - aside from having different scary-ass facemasks and builds, Salem and Rios have essentially the same abilities. With the money you earn on missions, though, you'll be able to deck out your merc of choice with fully customizable weapons, camouflage and armor, giving him an edge over his partner.