For the entire easter egg, minimum of two players must be in an online party. LAN party/System Link or splitscreen do not work. However, doing a part of the easter egg (to the point where it is possible to earn the Cryogenic Slumber Party achievement/trophy) is possible on solo as well. Doing the steps require lots of time, patience and teamwork, as well as some points and luck with obtaining the right weapons from the Mystery Box. Making a crawler zombie (by blowing a zombie's legs off with explosives to make the zombie significantly slower) whilst doing the steps at the end of a round helps significantly to give the player more time and freedom to do the necessary.
To complete the whole easter egg, the players must have the weapons/devices listed below:
The required weapons do not have to be obtained at one time, and can be used individually.
Not all of the following steps below have to follow the order in which they are listed and may be done as soon as the opportunity to complete them is available.
After turning on the power, return outside of the Receiving Bay on the Olympia's side in front of tunnel 6. There are four computer terminals lined up near a cliff. Each computer represents a color: red, green, blue, and yellow (colors change place if you fail or start a new game). When the step is started, all of the computers will flash one color. The player must press the use button on the computer with that color. The computers will flash again, this time with two colors, and the player will once again have to match them. This step will continue until all of the computers flash green and a message is heard. If the player messes up, the step is restarted.
Proceed to the second floor of the laboratory. On a wall to the left of the stairs leading to the third floor laboratory, there will be four dim switches lined up next to each other. One of these must be hacked for 500 points. After doing so, the player will have to search all 3 floors of the laboratory for four white panel boxes with bright green lights. A total of 7 panels is spread between the three floors, two on the top floor, two on the second, and three on the third. The player must hack all 4 lit panels within 60 seconds or the player will have to hack one of the red buttons again to restart the process, ultimately costing the player another 500 points for each failed attempt. Each of these lit panels makes a buzzing sound that increases in volume as a player reaches it. Once the player has successfully hacked four green light panels the player must head back to the four lined up Red Buttons, the player(s) needs to press all four of them rapidly. It is easiest to just go from left to right or vice versa rapidly pressing the 'use/action' button.
When the player is successful, they will all pulsate red, and the various buttons around them will flash as well. Additionally, the center of the Vril Interface on the front of the pyramid will now be indented.
The player must then let excavator Pi breach tunnel 6. Immediately after, take the hacker back to the spawn area, and hack the excavator terminal. Once the player returns to Tunnel 6, they will find the Vril Sphere (the characters refer to it as the egg but in truth it is a Vril Device) lying on the ground near the M16. The Vril Sphere must be moved into the center of the Vril Interface on the pyramid, or M.P.D . The Sphere must be knifed or shot to get it moving. Once knifed, it will begin to float towards a satellite dish on top of the spawn. If the egg gets stuck, simply knife it again or shoot it, and remember to open doors for it.
After it reaches the dish, it must be shot with the Wave Gun to have it fall down and travel towards tunnel 11. This is the only part of the easter egg where the Wave Gun is needed. Eventually the Sphere will get stuck in a tight corner in the ceiling, just above a barrier adjacent to the Stamin-Up perk machine. To get it out, either throw a grenade, or shoot any projectiles that induce splash damage (such as Ray Gun shots, although it can be freed with bullets if shot from the right angle). Then it will merge with the plate in front of the pyramid and a glass canister will rise from the floor close to the pyramid's corner.
A cylindrical container will rise in the front right corner (if the player is in front of the plate) of the Pyramid, the player must kill 25 zombies near this tube and have their souls sucked into the tube (the range is very short). Zombies that are killed within range will have a red stream of dust emit out and into the ceiling. Zombies killed via Nukes will count. When the tube is full it will make a sound, the player then pulls a switch that looks like the power switch on the left wall. The pyramid will open revealing Samantha Maxis and rewarding everyone with a 90-second Death Machine.
Go back to Area 51, and look to the right side of the teleporter. The player will see a beam structure with some hexagonal-shaped plates stored on it. Throw a grenade to get the plates down (the character will mention the loose plates if done correctly) and then throw a Gersch Device. If done correctly the plates should be on the teleporter with the player, and the player should teleport back.
The player should see the plates near the Quick Revive in the spawn room. The player must throw a QED on them so that they move to the right side of the room, and stand upright in two brackets on a small machine next to a computer.
Now the player has to look around the labs for a lead wire. It is long, curved, and silver, and is located on any floor of the labs. It may be on the ground, against a wall or crate, or inside any desk where the Hacker may spawn. This can be found at any point before this step as well. Also, it can spawn outside on the Moon near the entrance of the teleporter or by the crates to the right of the door leading outside. It can also spawn in the starting room by the excavator switch. Although, these three locations are rare.
Return to the spawn building, and locate the computer that the plates have moved to. Place the Vril Generator between the plates, and connect the lead wire between the two pieces of equipment. Have the person playing as Richtofen repeatedly use the action button on the computer to the left of the plates. The player will know it is working when they hear the sounds of computer keys being tapped. Continue pressing the action button until a voiceover is heard; listen to this voiceover until it is done. The player will know when he/she is done after the computer screen goes red, green, red then green again. The player will know the step is complete when the Vril Generator begins to glow brightly. Now retrieve the Vril Generator. (On the PS3 version, there is a glitch, if there is no gravity in the receiving area, sometimes you will not be able to complete this part of the easter egg.
Go back to the open pyramid. Four tubes will appear, and the player must kill now 25 zombies by each. After all the tubes have been filled, put the Vril Generator in the slot in front of the pyramid. As with step 4, you will know you are filling the tubes when red souls fly out of zombies. However, Samantha will also begin to scream and violently shake the screen as the tubes fill. Samantha and Edward Richtofen should switch souls after the Vril Generator is inserted, which will then give the person playing as Richtofen all 8 perks permanently. At this point, the Vril Generator cannot be removed from the Vril Interface on the M.P.D.
Throw a QED directly onto the Vril Interface symbol on the front of the Pyramid in the power room to make the Vril Sphere move again. It should launch over to the Simon Says machine.
Play the electronic color-game three times (one for each rocket). Unlike the first time, the game begins by showing the player the first three colors, then four, and five on the last time around. This makes it much more difficult to complete. If the player does finish it correctly, Maxis will say something about controlling the station, and asks you to move the Vril sphere.
(Note: Steps 10-12 are interchangeable and may be done in any order.)
Now take a Gersch Device and throw it near the Vril Sphere, if done right, the sphere will be teleported. Maxis will say something, and a countdown should start. The 3 rockets will be launched toward Earth (30–40 seconds) and incinerate it. Upon impact, the ground shakes severely, and all players will receive all 8 perks for the remainder of the game. The perks will remain even through being downed or death.
- Main article: Richtofen's Grand Scheme/Transcript
- After the player completes step 4, the players will all receive 90-second Death Machines.
- Richtofen receives all eight perks after step 9, the rest of the players get them after step 10 or 11 (depending on which you did last). These perks will last until the game's end and cannot be lost in any way.
- Two gamer pictures (Xbox 360 Only), one of Samantha Maxis and another of a Teddy Bear holding a Bowie Knife.
Cryogenic Slumber Party (75 / Silver Trophy ) - Awarded for completing step 4.
Big Bang Theory (100 ) - Awarded for completing the easter egg entirely.
- After the Easter Egg has been completed, Area 51 has a different appearance due to the Earth being hit by the missiles. Oddly, Area 51's appearance won't change if the players are in it when the missiles hit Earth, but will change the next time they return. In addition, if one runs as far forward on the left side after teleporting as they can and turn around, above and to the right of the building with the teleporter in it, they can see the Earth as if from the Moon.
- The Demonic Announcer is now Richtofen after completion of the easter egg.
- After Richtofen and Samantha switch souls, the eyes of all the Zombies become blue due to Richtofen being a Nazi and their ideals of having blue eyes meant purity, superiority and perfection.
- Following Richtofen switching souls with Samantha, the Fire Sale jingle will change to a different tune.
- This Easter Egg cannot be completed entirely offline (solo and local splitscreen) but Cryogenic Slumber Party can be achieved. It cannot be done because the Vril Generator will not appear in Richtofen's inventory while offline. The reason for this is because the player would have infinite Quick Revives and never die.
- If a player is standing on the pyramid while the sphere lands on the pyramid at the end of step 3, the sphere will miss and become stuck in a glitch, essentially ending the easter egg.
- If a player takes his P.E.S off their head right before obtaining the 90-second Death Machine at the end of step 4, the player will be unable to use the Death Machine or any of their weapons and equipment, and they will also be unable to sprint, for a total of 90 seconds. The player however can still use the knife.
- Steps 1, 2, 5, 6, 7 and 8 can be done in any order before step 3.