Three years after the game itself, there was a comic of Doom. Wouldn't that just be panel after panel of a guy shooting some demons you ask, coming scarily close to the truth? Yes. What the comic actually adds to the unthinking carnage is not plot, but a constant and inspired stream of consciousness monologue bellowed by the deranged hero Doomguy. Classic lines include, "Allow me to communicate my desire to have your guns!" and "Rip and tear your guts! You are huge! That means you have huge guts! Rip and tear!" Some choice panels, and a link.
Read the comic over at Doomworld. Afterwards, you can retire to the comments to discuss whatever the hell just happened to your brain.