Once you get 3,000 points, go upstairs in the zombie factory place. When your upstairs, if you used the main steps on the front start area, turn around. Go around the steps and go back to the back of the room near the sandbags until you see a vanity or dresser object behind a pillar. Go up to it and open it. You will get a flamethrower. Go around the pillar over to where the steps are located. Turn left and to find a room and a wall in a protected corner. Go in the corner and use the grenades behind you and your flamethrower to kill.
ltbglrtn auitawi rirdrylau tayn Arron Baker

If you unlock the storage room, there is a radio on the barrel by the Teddy bear that has the voices from the Verrukt video.
Tony

To get a free Wunderwaffe DG-2, open all areas but do not get the Perk-A-Colas. Once you get them all open, you will receive a shovel when you use the knife. Search for a mound of dirt. Tap the "Dig" action button to receive the Wunderwaffe.
Tony

After you open up all areas, the middle of the map is the best location to go. You can just run around there in circles. By doing this, you can make it to round 38 by yourself.
Oscar A Esparza

Clear the debris to the upstairs area. Go upstairs. When you first get to the top, you will see an area where you can resupply grenades. Go directly in front of the grenades and have your back towards the grenades. You are now in a good camp-out location. Because you are on the top floor you have access to the flamethrower, the trench gun, the BAR, and grenades.
Andrew Fusco

Unlock the "help" room. Once there unplug your charger and plug it back in. To exit, do the same thing as you did to get in. Note: You are invisible to the zombies the entire time. If you are having trouble killing them, shoot up and you will get a zombie or two.
gamecrazyben

Strategy guides from GameFAQs