Hint: Play Colonial Marine In Campaign
Current Rating: Not Rated
One of the reasons you should have a buddy or two to play this game is to force the computer to let the other players play the Colonial Marine in the initial few stages before the whole team is completed.
The Colonial Marine acts as a stand-in for the other three Brute Force Squad Members, and has a one-use special ability (Ion Cannon). The only way to recharge this weapon is to die (as the Marine) and respawn.