"The Portland Chainsaw Masquerade" mission hint
As soon as you enter the tanker, go straight until you see a hall to your left and one to your right. The right hall leads to a Magnum, which has decent one-hit kill shot power. Take the hallway that was toward your left to find a second hall to your left. Go down that hall to find Body Armor. Continue down the stairwell to begin the fight. Using the Magnum you picked up, take out the Leone goons. Don't try staying in one area and shooting them all down. After you are surrounded with two or more goons, run around the room until you create a good distance between you and them. Continue aiming and shooting down the Leones until an intermission sequence shows a stronger goon entering the hold. Use the remaining Magnum ammo on him, then use another good offensive weapon. Finish him off. If you finish this mission quickly, he will leave behind a powerful sub-machine gun or AK. You will unlock both the Overalls outfit (Jason attire) and the Chainsaw TV mini-game event.