ATTENTION!- This guide requires 3-4 people, and getting good weapons from the mystery box.

Round 1-4
You're going to want to stock up points in the first room on the first 4 levels. Round 1 and 2, Let them in and knife/shoot them for powerups. Round 3 and 4 you can let them in, but be prepared to use grenades. DO NOT BUY A GUN IN THIS ROOM!

Round 5-7
Now, you want to open the door upstairs and then the next one, or until you're in the room with the Stakeout and MP40. I suggest that you buy an MP40. At one of these rounds you will get a dog round. (Dogs drop a Max Ammo everytime, so just use up your ammo haha) For the zombies in these rounds, you will want ONE person downstairs on the 2 doors, and 2 or 3 upstairs (MAKE SURE SOMEONE IS COVERING THE BLUE BARRICADE UPSTAIRS) 2 of you need to be covring the stairs.

Round 8-10
After round 7 leave the MP40 room and buy the next 2 doors immediately. DO NOT TURN ON THE POWER YET! You should be at the Stage now. Have one person guard the back window and be a support role if you need them. The rest of you (2 or 3) need to sit infront of the place where the mystery box is. 2 of you crouch and 1 of ou stands over and moves out to get Power-ups. The reason you do this is because if you're all right there the zombies make a line and are easy to collat and kill Make a crawler on round 10.(Remember NEVER move, unless you are being COMPLETELY overun, many a time have I been the last man standing in this situation because ONE teammate moved from postion.)

Round 10-30
Now this is where your previously made crawler comes in handy, find the mystery box an hit it until you have good weapons, you want atleast 2 LMG's, a Raygun, and a Thundergun. (Cymbal Monkeys are a lifesaver) Once you get the mystery box and are content with your guns, open up the door on the stage, next to the M16. go through this room and go downstairs to the Alley, open up the fence and this is where you will hold your own against the zombie horde. DON'T EVER OPEN UP THE DOOR AT THE END OF THE ALLEY ON THE TOP OF THE STAIRS!
If you open it, your amazing zombie-killing-camping spot is RUINED. You will want whoever has the LMG's infront of the steps looking toward the Horde, one person with support weapons (Raygun, Thundergun, Cymbal monkeys, crossbow etc.) on the top of the staircase, and one person guarding the window (This person should be the one with the "worst" weapons, like assault rifles, or SMG's or Shotguns. You can make a crawler and turn on the power and Pack a Punch your weapons now, Jugger-Nog is a neccesity. Now, you are set until round 30.

That is how you can make it to round 30 relatively easy, after that, you will want to make laps around the map. Goodluck and have fun. Haha

If this guide has helped you, Rep would be appreciated