One of the random encounters is a "Crashed spaceship" that has a label reading "Property of Area 51. Return if found" on it. By the spacecraft there are two alien bodies of which one has Elvis Presley's photo in it's inventory.
Creator Tim Cain developed the game's concept from a dream in which people fled into the safety of underground vaults to avoid nuclear catastrophe.
One of the random encounters when walking across the desert is a blue police box, standing in the middle of nowhere. It disappears when you approach it. This is a reference to Docteur Who (1963).