Okay, first don't expect one of those crazy things where is says "Call of Duty: Black Ops" in miscellanious characters arranged in miscellanious fashion. I don't have that type of time because I'm typing this as I play nazi zombies on "Five". Yes, this strategy is that good.

This strategy--like most strategies for nazi zombies--works best with four people, but for me it was very effective when I tried it alone. I still have not done it with two or three people, but it works ingenuinly with four. Now, do you want to know what the strategy is? Well too bad. LOL JK here ya go:

First you'll start off in the two rooms containing the Olympia and the M14. At least two players should grab the M14 while only one(recommended, but hey don't listen to me, I only got to round 40) should grab the olympia. For the first two rounds you should only use your knife to kill the zombies in order to rack up as many points as possible. Not all windows are used in the first room until you leave, so plan out the defense of said windows according to which are being attacked by the zombies. After round 2 at least one of you should have 750 points and a fully loaded M14. The person with the most points should open the door leading to the hallway containing the MPL and the elevator.

The person with the shotgun should be stationed near the elevator and be keeping an eye on the two windows there while one other person runs up and down the hall blasting the zombies that break through the walls. Two people with M14s should stay back in the first area and rotate themselves around the six possible entrances that zombies may come through. When each player accumulates enough points they should immediately open the elevator(but do not go down yet) and buy the MPL. It is wisest not to use the MPL until round 4 or 5, but you will move on to bigger and better weapons when the time comes. Use this strategy until each player has at least 1250 points. Once all players have 1250 points they should all retreat to the elevator.

Once retreated to the elevator, everyone should be using the MPL. Two people should still be containing the zombie threat from the two windows by the elevator while the other two are acting as a firing squad on any zombies coming from the first area or the holes in the walls. Those two, acting as a firing squad, should be just in front of the two manning the windows, preventing the zombies from reaching to men on the windows. While doing all of this the two players shooting down the hallway should also try to throw one well-placed grenade in order to blow a zombies legs off, making that zombie a crawler. DO NOT KILL CRAWLERS!!! The only time it is ok to kill a crawler is when there are more than one. The point of creating crawler zombies is so you can run around and repair all of the windows while the crawler chases you. It will help tremendously later on and it racks up a small sum of points as well. If you and your allies start to become overrun by zombies in the hallway, retreat to the elevator and head down to the second level. Also, if the crawler comes near the elevator you should retreat down to the next level. With all of that said once you have one crawler and you're sure he is the last zombie left you should run around the entire area and board up all of the windows.

Once downstairs you want to open up the stairs leading down to the base floor. Then you should proceed to open up as many other places as possible, but the most important place that should be opened up is the big elevator on the ground floor. If there is just a crawler left, as planned, three people should grab the Stakeout, the shotgun near the elevator, and the other player should grab the MP5K which is on the catwalk up top. Now that you have your weapons retreat back upstairs, kill the crawler, and get ready for the next round.

If you retreated downstairs because the zombies had overrun you on the upper level, you should all retreat to the big elevator on the bottom of the level. Make sure one person grabs the MP5K on the way there and,the other three grab the Stakeout when you get down there. One person with a Stakeout should get to the back of the elevator and hold that window down while the other three are unloading hellfire at the zombies coming for the elevator. Make sure you make smart reloads; reload when it seems that the zombies have let up for a moment. At this point you should still be trying to make the last zombie a crawler. Once there is only one zombie left as a crawler take the crew down another level. 

Everyone stick together down here. Run to the back and turn on the power then retreat back up the elevator. Activate all of the defcons except one then retreat back to the top floor hallway. Kill the crawler and get ready for the next round.

Keep repeating the strategies above until every player has amassed over 6000 points. When all players have enough points and there is just a crawler left, take the elevator on the top floor down and turn on the last defcon. Upgrade your weapons with the Pack-A-Punch for 5000 points. Now that we have some beast weapons, it's time to find the mystery box.

Again, keep repeating these strategies until everyone has about 3000 points. When there is just one crawler left go down to basement(using the big elevator on the defcon level) and open the door to the room containing the mystery box. This room is located to the left of where you exit the elevator. DON'T REPLACE YOUR UPGRADED WEAPON!!! Choose whichever weapon you like out of the mystery box, and once all players have a sufficient weapon, return to the top floor. On your way up activate three defcons. Use the Pack-A-Punch strategy to soup-out your Mystery Weapon and have fun surviving. 

When the Evil Scientist Zombie comes("Attention: the pentagon has been breached") have everyone get into a corner with their least effective gun and unleash hell on him. It is best to be on the basement floor when he comes. If he takes your weapons simply chase him down and take them back.

I'm sorry this has been a lot to remember, but it is a pretty good strategy. Really, it's not too much to remember because it only took me two attempts of playing(the best ending at round 11) by myself to think of this. Once you get the hang of it you'll do fine. Good luck fellow zombie slayers.