Mass Effect 3 "Integrated Co-Op Multiplayer" Trailer

Form an elite strike team with three of your friends, then work together to liberate key conflict zones in an action-packed co-operative multiplayer mode. You'll start as a human combatant, but through a deep progression system you can unlock other powerful races and classes. You will need the other classes' unique play style, powers, and abilities – plus other unlockable rewards such as weapons, armor, health and damage boosters, and upgrade kits – to defeat increasingly deadly waves of opposition. But above all, you will need teamwork to survive.