Mindjack

Bit of a morally tricky this one. You need to hack into someone else's game and play as a red Hacker. To win a round, you need to down both main characters and have them counted out. This can be v tricky if the blue player is half decent and so it helps if the level is further on with trickier enemies. Also be fair to the blue player, and maybe let him know what's going on or he'll probably kick you after a couple of rounds!!