Win the Eliminator, Deathmatch, and Endurance titles with the same character on the hard or very hard difficulty setting to unlock Buzzsaw.
Extra Goodies
At the aircraft carrier level, blow up all of the planes around you. There should be one big explosion. If you look close, a piece of the ship will be missing. Go down in there and there will be a mini nuke, chaingun, and health. Then to get out go through the blue portal.
City Canal arena
Finish all of the Deathmatch level on the normal difficulty level and the City Canal arena will be available in the mutli-player and quick battle modes.
Downtown arena
Finish all of the Eliminator levels on the normal difficulty level and the Downtown arena will be available in the quick battle modes and multi-player mode.
