nice video dual but i noticed the guy barely takes any damage from the zombies when they hit him, which means he's just doing the console commands in a normal or even easy mode game.
In expert mode the zombies hit for about 10 to 30 damage each swipe and boss zombies do about 30-60 damage a pop when they pounce/smoker choke. Not to mention tanks instantly incapacitate
. With that many zombies you probably could barely make it off the rooftop.