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.
Extra radio
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.
Get a Good mystery box gun
Ok get at least 3000 points open the doors I need to open don't use All your M1911 Amo ok then go to mystery box knife it 2 times and shot it 3 times it has a 50-70% chance of working even higher if power turned on at same time.
Great gameplay
First rack up as much as you can and continue to knife and use your pistol. When you hit 16 bullets left buy the $200 gun in the main room near those 2 barriers. Next finish your pistol off and start to use your other gun. Once you hit $1950 open the help room so then you have $950 for one shot at the box. MAKE SURE YOU TAKE OUT YOUR PISTOL WITH NO AMMO AND DON'T TRADE THE OTHER GUN IN!! Remember to always use the gun you got from the mystery box first and not the main rooms wall guns in the help room at the back there are 2 guns the Thompson and the Double Barrel Shotgun. TIP. NEVER OPEN THE OTHER 2 THINGS EVER REALLY OR YOU'LL DIE WITHIN 10 ROUNDS. From there until round about 7 you can roam free and go in either room but at the end of round 7 pick one room. (Suggested pick the help room) Stay in that one room and at the end of every round either make 1 of 2 choices. Rebuild barriers or buy a new gun don't try and squeeze in both or you'll be in trouble. I say at the end of round 15 if you make it that far open the stairwell in the help room NEVER EVER EVER EVER EVER EVER OPEN THE STAIRWELL IN THE MAIN ROOM OR YOU'LL END UP DYING THAT ROUND!! Go into that room with the grenades and camp there. Always buy greanades because you will have plenty of money and throw them down the stairwell. At the end of every round go and get a new gun (unless you have 2 amazing guns) STILL NEVER OPEN THE STAIRWELL IN THE MAIN ROOM. That's it and just so you know I do this alone and my highest alone doing this is level 31.
How to make a Crawler
This one's easy; just throw a grenade at a/some zombie/s and that will turn them into a crawler. Make sure the grenade lands next to the zombie, or else the zombie will die. You can use crawlers to explore the map, Pack-A-Punch, buy weapons, and open doors without get trampled by zombies.
Nacht Der Untoten: Easy kills
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.
Nacht der Untoten: Mystery box
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.
Open doors with out using money
Ok to start off u need to play co-op or you'll just die so when u start if there's a 1000 dollar door get at 1000 or more then go to that door cook a grenade counting down from 5 to 1 when finish hit the open door sign and you'll go down but you'll have same amount of points also works on mystery box.
Ray Gun
If you only use your knife through level two and between level two and three get the 'Nacht der Untoten' mystery box you will get the ray gun.
Shino Numa: Easy survival
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.
Wunderwaffe DG-2
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.