The new Mann vs. Machine cooperative game mode for Team Fortress 2 is now live! The exciting new mode pits you and up to five other players against countless waves of robot attackers (think zombie/horde mode).
You are far from defenseless however, with the ability to upgrade abilities and weapons to turn robots into nothing but scrap metal. There are a number of missions to take part in, and achievements to unlock.
Mann vs. Machine is free for download for the PC and Mac, and you can head over to http://www.teamfortress.com/mvm to check out the full details.