I am only doing this guide to solve any confusion. 1st person experience, sorry that i have no video footage but i got the achievement about an hour ago.

Ok, so first of all you will need the power on.

Step One - Once you have made a crawler, one person or more (doesn't matter) goes back to the spawn area and plays Samantha says which is a memory game on the four computers just underneath the spawn room.

Step 2 - Now one play will have to grab the hacking device which can be found in one of three rooms which is just up the stairs near the pyramid where you turn the power on, the device will be on 1 of 6 tables. once one player has the hacking device in the second room there will be 4 mainframes, the leftmost one has to be hacked. Once the player has hacked the mainframe he/she will need to find FOUR control panels on the walls of the three rooms in a given time. This will now allow the mainframes' buttons to be pressed, get each player to get on a button and press in sync (this can be done with 2 people).

Step 3 - Once tunnel 6 has been decompressed (the earlier the round the better) you will need to hack the control panel of that Digger (I'm going to call it that cos i don't know the name of it) to stop it from sawing. Now go to tunnel 6 and there will be a Weird Ball in front of the door, you will have to knife this and follow it, if it stops continue to knife it. once outside the ball will get stuck on a satellite, now you will need the wave gun. shoot the satellite with the wave gun and follow it through tunnel 11, while in tunnel 11 it will get stuck and you will need to shoot it out of a hole in the ceiling. follow it until it gets to the pyramid, once at the pyramid a tube will come out of the top left corner of the base of the pyramid.

Step 4 - You will now need to fill the tube with zombie souls and to do this you will need to kill zombies in a radium of that tube, eventually when the tube is full you pull the leaver and Samantha will come out of the pyramid and you will get the 75g achievement and a death machine for about 2 minutes.

Step 5 - Now you will need gersh devices and them new special grenades. head to the teleporter which takes you to the pack-a-punch machine and teleport. While there one player needs to throw a grenade at the shelves to the right of the perk machine and the player with the gersh device has to throw one in the same place. once out of the teleporter and back in spawn room the player with the new special grenades has to throw one at the plates which are on the floor in front of the quick revive machine. now you will need a blueish grey wire which can be found in the same rooms as the hacking device. take this wire back to the spawn room and in one of the corners is a computer, you need to put it inbetween the computer and the thing with the plates on by holding x. now Richtofen will have to put the golden rod inbetween the two plates and keep pressing x on the computer until the screen goes green the second time and then he should retrieve the golden rod from inbetween the plates and take it to the pyramid. on the front of the pyramid is like a giant disc and the bottom hole is meant for the golden rod now attempt to put the golden rod in that hole and 4 tubes will come out of the pyramid which you have to fill.

Tip: don't pull the leaver to get the death machines until this step

Filling the tubes: This can be very difficult on higher rounds. It would be best to have Juggernaut and packapunched weapons for easier kills, or a Ray gun

Step 6 - Now the tubes are filled, Richtofen must now put the golden rod inside the hole it fits in. I belive you hear some dialogue and richtofen has all the perks and now you will need another gersh device and other new special grenade. you will notice that the ball from step 3 is now slightly to the right, to move this you will need to throw the new special grenade at it, this will make it appear near the 4 machines near spawn. You will have to play another Samantha says but it will be harder than last time. You can do Samantha says before you move the ball its up to you. When Samantha says is done the player with gershes needs to throw one near the 4 computers and then the rocket will launch, everyone will now have all the perks and when earth is blown up you get the Achievement. (YOU HAVE TO MOVE THE BALL BEFORE U THROW THE GERSH DEVICE)

Hope this has helped