The ... Book Series
I am the proud owner of a pair of books bearing the Doom name. Written by Dafydd ab Hugh and Brad Linaweaver, the first one, Knee-Deep in the Dead (so named for the first episode of the game), has exactly 250 pages, while the second, Hell on Earth (so named for Doom II's subtitle), clocks in at 248. They were published in 1995 by Pocket Star Books.
Now that that's, out of the way, I am going to provide quick disclaimer: Do not buy these books. I bought them used for a dollar each, and I was cheated. Whoever payed 5 bucks for each of them was robbed blind. I threw down my money for then because I wondered what sort of literature could be coaxed out of the license. I got my answer, and now that I have it, I'm getting rid of them.
With regards to basic plotting, they do follow the game. Oh yes. If I may quote czeano above:
As a penalized Space Marine, the player has been assigned to babysit a military research facility on the Martian moons. The major scientific project being studied involves inter-dimensional gateways. The gateways get out of hand and open a portal to Hell.
The player's unit gets wiped out by the critters that poured out of the gateway, and now it's time to push 'em back.
...
After defeating the game, the player is enters another inter-dimensional portal that happens to leave back to Earth.
Unfortunately, the hellspawn got there first.
DooM II picks up immediately afterward, with the demon army trashing Earth and leaving the player to pick up the pieces.
Right. Imagine 500 pages of that. Oh yeah, plus other characters. And Mormons.
No, really. See, the second book required a bit more creativity, as the entire plot of Doom II consisted of those two above-quoted sentences. Thus, Mormons. They were the only ones to survive the demonic holocaust with organization intact, and the protagonist hooks up with them. Thankfully, this book sees the end of chapters that read like fucking level walkthroughs. It also sees the beginning of George Romero zombie cliches. It's a fucking joy.
I'm not going to go through any more specifics of the plot. It hurts even to think about what I have written so far. Thus, what follows is a description of the characters. Such as they are. Starting us off is Flynn "Fly" Taggart. He's the good guy, with about as much personality as the player's avatar in the game. That is to say, nil. Next is Arlene Sanders. She's the love interest. Bill Ritch is just this guy, whom the protagonists rescue from the big evil spider-demon thing. Introduced in the second book are, to quote the book's back cover, "a fourteen-year-old female computer genius (and) an unrepentantly Mormon sniper". Can't for the life of me recall their names. In what's his face's credit, the former is not as cardboard as she could have been. Oh, and lots of demons, zombies, cardboard Mormon leaders, and a few live, treacherous humans.
Just a few more notes: scattered throughout are references to what are obviously in-game items, like health packs and those blue sphere-things, and speculation on how they actually work. This is funny. Also, the second book ends with what is obviously a segue to a sequel, but it comes at an odd place. My guess is that the authors said "Well, shit, we're within 2 pages of quota, let's end this crap." There may well have been more books. I know not.
BEYOND THE GAME... THE FIRST CHAPTER IN A CLASSIC NEW SPACE OPERA
dRiVeN notes: "There were actually two more, "Infernal Sky" and "Endgame" - they had less to do with the game but were still crap."