Pack-a-punch - Activate pack-a-punch by following the in game hints
Button - Now go over to one of the big windows in the Observation Tower and to left there will be a small red button on the wall which will play a cutscene
Chrsyalax - Build the free Chrsyalax, hope to find one in box, or hope to get one from trials.
Fuel Tanks - Go to Fuel Processing. On all the big tanks there will be a panel to interact with. Interact with one of them. This will now start a lockdown. You have to fill the tank with zombie souls. If completed a big part will spawn in the middle. If failed you can retry next round.
Aether Crystals - go to Storage Zone 5 Rooftops. There should be a big crystal with a few small orbs flying around it. Shoot all the orbs until they go away. Once you break one an endless wave a zombies will appear. once all the orbs are gone, melee the big crystal with the Chrsyalax. Now the crystal should go away and there should be a shard to pick up inside of it. Now the shard should be in your equipment. An abomination will spawn and you have throw a shard into its glowing mouth before you kill it. Once you've thrown the shard in kill it and if done correctly a part should spawn. You now have to do this at two more locations, The Amplifier, and at the Staging Area back at spawn.
Arcade Machine - Put dead wire onto one of your guns. Now go into the Arcade and go to the machine that says Grand Prix and that is turned off. Kill a zombie with dead wire next to it.
ARC-XD - From that arcade machine buy a ARC-XD. Now drive over to the TV Store across the street. Now go behind the counter and go over to the vent. Wait for the small blasts to open the vent. Now drive into the boxes next to the shelf and detonate it. Now go over to the TV Store and pick up the part that is where you blew up.
Housing Unit - Go to the Board Room which is near The Amplifier. Now there should be something dangling on one of the walls in a corner. Stand under it until the Abomination charges into up. Now the part should be on the ground to pick up.
Neutralizer - It is recommended to get the perks you need, the armor, and upgrade your weapons before this. Go to the end of Main Street (If you are playing with anyone make sure they are here too) and go to the workbench and build the neutralizer. Now wait a few seconds and interact with it and it should start rising. Now you will need to follow the neutralizer and stay in its bubble. Once it stops moving go a bit outside the bubble and break the red crystals to get a shard and place it in the neutralizer. You might need more than one. Do that the entire way until you make it to the end.
Boss Fight - Once you finish the neutralizer you should have one last chance to get all the stuff you need. Make sure to buy a death machine (If your playing with anyone have them buy it too). Once ready open up the big door. Now you will be in the boss fight. Wait for Maxis to fly away from The Forsaken. Now stand her and kill as many zombies as possible in that circle. Once she moves away follow her and do the same thing. Now use the death machine to shoot the two shields on his shoulders. Put the death machine away when done. Now go onto both of the turrets and use one to shoot at one should and use the other to shoot at the other. This will bring his health to half. Now repeat this same process again to get the turret fueled. Now the two shields will be one his chest and one his head. Use on turret to shoot the chest when the shield is gone and use the other turret ti shoot his head when the shield is gone. Don't panic when you start taking damage and get downed because that is supposed to happen and that means that you've completed the eatser egg.