Solo-Get some friends
If you dont want to read this wall of text for a good strat, I will sumarize it in a sentence below.
Online-First room until round 4 (Usually when I run out of ammo) then open the first downstairs door. Do not buy a gun until you open the downstairs door, if you are out of ammo at rd 3 just ask for help/use grenades. This strategy requires 3-4 people. Enter the room, and two people turn around and face doorway (after purchasing the SMG on the wall to your right). This allows the zombies to make a pretty uniform line in order to get max headshots. The other two (or one) people watch the two windows on either side of the room. These people stab as much as possible for max points. The windows get light every now and then, so window watchers can run to the middle and help with the hoarde.
DO NOT TRY TO HOARD POINTS. If you get an instakill and decide to go run around to get all of the kills, I will not save you when you go down. If you ran for a powerup and died, it is because you are bad, not because no one will save you. Dont go stand infront of the theater doors to get the kills first because you will be flanked and I wont save you. THis will lead to you quitting and me having to find a new partner.
As soon as the middle starts getting over run (or window if you only have 1 window watcher) The hallway watchers yell run and everyone goes out the back door. This is usually around round 8 or nine. If the box is in the alley, it is possible to hold it down for a round this early on, so people can get a good weapon.
MOST IMPORTANT INFO- DO NOT RAPE THE BOX. hit the box once. I promise you will get a useable weapon. At round 8 or nine, the only thing you will pull that absolutely wont work as it is, is the Ballistic knife, and the crossbow. You dont need a ray gun, you dont need a thundergun, you dont need an HK, ect. You need a gun from the box, be it the python (another lower tier, but it works) or the RPK (Best non pap'd IMO) you just need to grab a decent gun.
Now you have made it the back way to the theater. Do not turn on power, and do not open doors. If the box was not in the alley, or on the stage, buy the m16. 3 people walk straight forward, stop, and turn around near the back side of the stage. If m16 is the "right side" STAY ON THE RIGHT SIDE. One person (the fourth, or third if you are shorthanded) will watch the window in the back. If your teammate tries to go on the left side, they wil be overrun and the window watcher will be flanked. Besides the back window, all zombies will come from straight ahead through the doorway, and window right next to it. Stay towards the back and they will come straight for you.
THis next part is dependant on skill. If you have a bad team, it would be wise to get the power on before the next dog round. If your team is decent, and you can survive dogs II without Juggernaut, find a corner or run around, just stay on the stage and dont open anything. This spot is relatively easy to hold down until you have 20k points or so, if your team isnt horrible. If you didnt turn the power on, stay in this formation until you are getting over run. Only then should you turn on the power and get juggernaut. If you already turned on the power, here is the end part of my strategy.
Link the teleporter every single round, keep a crawler to do so if you need to. In later rounds, you will need to link it mid round. Even though you will be in the PAP room, it is not worth the points to upgrade until level 16 or so, unless you are out of ammo in your ray gun or thundergun. You get far mroe points with regular ammo than you do with PAP ammo in the earlier rounds, and it simply isnt worth 5k to lessen your overall points.
Sit in the teleporter until you are swarmed by zombies (usually when someone starts getting hit). Travel to PAP room, throw as many nades as possible down into the theater before you travel again Do not shoot bullets. Grenades are 250, you cant buy bullets (for good weapons). once you do, head upstairs, and make the opposite lap that you entered the theater with. This will involve opening all the doors, so if you raped the box, or upgraded both of your guns, you will be broke, stuck, and I will let you die.
Make your way back to the stage, looking forward always so you dont get trapped. They WILL be in the dressing room and the WILL be crawling on the stage. DOnt back into them and die. Repeat until round 15 or 16, then make a crawler and find the box. your team needs atleast a ray gun, and a thundergun. If you plan on making it far, monkey bombs, ballistic knife (pap'd), and crossbow (pap'd) are necessary.
These later rounds are where it comes in handy to not have raped the box on round 4-5-6-7-8. I will gurantee that you WILL go down. At some point you will be swarmed, and not be able to escape. If you listened to this strategy, even if you die you have more than enough money to go buy every perk you want+box+PAP. If you upgraded your hk and ray gun on round 6, you are broke, and will go down everytime anyone revives you. You might as well leave now.
That is prety much the remainder of the game. By round 25-30 you will be hitting the teleporter 3 times a round, having to link it during your laps. For the dogs, everyone stay on the stage, and run in the same circle. Turn on the turret, and it destroys them. You will have to hit the turret multiple times, so dont hit it and then run away. THat will cause dogs to chase you away from the turret and not get killed.
In a nutshell: DOnt play rounds 1-15 under the impression that you will die at round 15. If you plan ahead to the earlier rounds, making it past 30 is simple. If you try to have a PAPd thundergun at round 9, you will never make it far.
Again, sorry for the wall of text, but it is a strategy, and Id only imagine the people against reading it............shouldnt be in this thread in the first place. I also know that the majority of people I play with ONLY go upstairs, and wouldnt even consider going down, so if you are one of them, dont flame my strategy until you try it. I promise it works.
Happy zombie killing