DoomGuy (Doom 2) VS Serious Sam (SS3) vs Gordon Freeman (Half-Life 1)

RULES: Doom Guy has every weapon, minus the BFG. Serious Sam has every weapon from SS3, MINUS the laser entrapment thing. Gordon Freeman has every weapon from HL1, minus the Gluon Gun. Field of Battle: a 200x200 foot cube, covered with moist dirt that goes 7 feet down. Below that is solid rock that cannot be broken without extreme explosives. Nothing else is on the battlefield, just dirt and stone. There is no time limit or respawns or extra enemies. If you run out of ammo for something, you don't get any more. There are no health pickups or armor pickups.