Escape From Natas (EFN.WAD)

First, there was Escape From Phobos, where Snake Plisskin awoke in the throes of an alien invasion of Mars, tasked by one John Carmack to come to Deimos and rescue him. Then there was Escape From Deimos, where Snake reached Carmack's research complex only after he had been undone by his own horrific discoveries. And now, Escape From Natas. The finale to Snake's extraterrestrial adventures bears more resemblance to EFD; released in 1997, almost all the action is contained in MAP01, with a brief adventure in MAP02 to serve as the true culmination of the player's efforts.

Escape From Deimos (EFD.WAD)

ESCAPE FROM DEIMOS
by Chris Christenson
and Nicol Jarvie

Escape From Deimos is the second in a trilogy of works by Chris Christenson (with help from Nicol Jarvie) that are supposed to take place roughly concurrently with the events of Doom. The protagonist of this exercise, however, is none other than Snake Plisskin, hence the title. Rather than a minisode of sorts for this second entry, Christenson restricted himself to a single map, this one also for Doom II and also released in 1997. In Phobos, Snake was released from suspended animation in a desperate bid by the Deimos project coordinator, one John Carmack. In Deimos, Carmack suffers a violent death off camera, with your actions after finding his corpse documented in the followup, Escape From Natas, where the rest of this story's assertions are made.

Escape from Phobos (EFP.WAD)

Plenty of people have tried to tell their own stories through Doom. Some of these people have dovetailed it with other worlds. Chris Christenson didn't just throw in a hot movie property, though. It's more like the world of Doom was drafted into Snake Plisskin's. Escape From Phobos is the first in a trilogy of small mapsets, followed by Escape from Deimos and Escape from Natas. This installment, released in 1997, is a three-level minisode that replaces the first three maps of Doom II. It's got a .DOC file that explains the story, and if you care to indulge in Christenson's exploitation of Carpenter's beloved anti-hero, you're more than welcome to read it in full.