A 4 person strat is to have 1 person in the dirt hall way one at the window at the top of the stairs and the other 2 downstairs with mgs or ray gun. the guy in the dirt hall takes nades off the wall and throws them into the room where the other 2 ppl are or out the little opening in the wall to make crawlers and injure zombies. everybody needs betties to put in the room for back up. if the 2 need to fall back either go up to the top of the stairs or down the hallway. good strat if everyone works together