I've been playing Nazi Zombies a lot lately, so here are my Der Riese plans:
At round four (five if you can withstand four with only your Colt pistols in the starting room), open the door to the Trench Gun room. Take turns opening doors until you can get to the room with the Mystery Box. Buy random weapons and Trench Guns until everyone has something good or the box disappears. Hold up in that back area until everyone has enough for Jugger-Nog, then go and get that (and Bouncing Betties if needed). If the box moved to the room where Teleporter C is, open that door (where the Bowie Knife is), or keep holding out in the room where the Mystery Box first appears (without opening the back door) until everyone has a good amount of points. Then make a crawler and keep it alive so the team can freely run around and link all three Teleporters to the mainframe. You can do this by evenly dividing up the tasks of opening the remaining doors, or by letting part of the team open the doors so one person will definitely have enough points to use the Pack-A-Punch Machine. You might have enough points to buy other perks, but none of these are as important as Jugger-Nog. The best place to hold up for the remainder of the games is probably in one of the Teleporter rooms against the back wall, since it gives you more space than one of the catwalks, and you can use the Teleporter if you need to escape. If anyone needs to use the Pack-A-Punch Machine, make a crawler so you can use it without worrying about getting downed.
The Bowie Knife is effective as an instant-kill in earlier rounds, but don't buy it unless you have an excess of points. Jugger-Nog is much more important. In later rounds, it is less effective, but much more useful than your standard knife. Either buy it early or buy it later after you've used the Pack-A-Punch.
Even though you might want to stay near the Pack-A-Punch once you unlock it, the starting room is not a good area to defend since zombies can come from almost any direction, and it's very hard to reach downed teammates in other parts of the room. The first Mystery Box room is a good place to defend until you open the back door, since zombies can only come from one direction, and there's an electric barrier under the bridge.
Der Riese is much more difficult than Shi No Numa since once the Mystery Box disappears, it's more difficult to find again, and it usually warps to areas that are not very easy to defend.
The most important thing to remember in Der Riese is to STAY TOGETHER! The only exceptions should be when linking the Teleporters to the Mainframe, and that should be done when the coast is clear and you only have one crawler remaining. If someone gets downed, it can be very hard to revive him without getting everyone else downed as well. If you die, you will respawn close to your teammates, but it can be very hard to get back in the game unless you have a lot of points and get lucky with the Mystery Box quickly. Also, after getting downed, you lose all your perks. Without Jugger-Nog, it's very easy to get downed by a single zombie that sneaks up on you in all the confusion.
At round four, it's much better to open the door to the Trench Gun room than the Thompson room. The Trench Gun can be an invaluable weapon early on (it's very useful against dogs) and a good backup if you have bad luck with the Mystery Box, whereas the Thompson will lose its effectiveness quickly. It's also much easier to get to the first Mystery Box room from the Trench Gun side than the Thompson side. Teleporter A, the Jugger-Nog machine, and Bouncing Betties are also on the Trench Gun side.
If you're lucky enough to get the Monkey Bomb, it is most useful when trying to rescue a downed teammate or when waiting for the Mystery Box or Pack-A-Punch. Be careful not to replace it with the Molotov Cocktail! The Monkey Bomb takes a while to wind up, so it's important to let your teammates defend you before you throw it. It's a powerful weapon, but not very good in a pinch because of this.
If someone is lucky enough to get the Wunderwaffen DG-2 early on, it can be useful for shooting the horde of zombies running into the Teleporter C room. Have the guy with the Wunderwaffen sit outside on the edge of the catwalk and shoot the zombies from above. The teammates should cover the nearby window and anything that gets up the stairs on the inside.
That's all I can think of right now. I hope this helps anyone who plays Call of Duty: World at War.
