Ok so lets start off at the easter egg:
So Richtofen the evil mad scientist guy switches bodies with Samantha, making Richtofen the "Ruler or something.." of the zombies. So, now whenever you get a power up (Max ammo, Insta-Kill, Deathmachine etc.) you hear richtofen say it. Also the zombies eyes become blue.
So Samantha wants revenge for switching bodies and killing/making him dissappear right after the 3 rockets go to earth. Then, Takeo the annoying guy gets his memory back and wants revenge and wants to destroy 115 or something.
Now, if you teleport back to