"Over the centuries, mankind has tried many ways of combating the forces of evil... prayer, fasting, good works and so on. Up until Doom, no one seemed to have thought about the double-barrel shotgun. Eat leaden death, demon..."
"Rip and tear! Rip and tear your guts! You are huge! That means you have HUGE GUTS! RIP AND TEAR! Oooh, here comes the night train! Choo choo cha-BOOGIE!"
"Who do you suppose left all that radioactive waste down there? And why? Why? Now I'm radioactive! That can't be good! Why can't we find a way to safely dispose of radioactive waste and protect the environment? Even if I personally stop this alien invasion, what kind of planet will we be leaving to our children? And our children's children, and... oh the humanity: my big gun is out of bullets!"
"At this particular moment in time, I don't believe I have a healthier or more deeply-felt respect for any other object in the universe than this here shotgun..."
"I'm the man! I'm superbad! Imps? Zombies? You think you can get me?!? Wait, maybe they don't think. Well, I do! And I think you're dead! Dead! Dead! Dead!"
"The poets talk about love... but what I talk about is Doom, because in the end, Doom is all that counts."
"If you haven't paid for DOOM, you are playing illegally. That means you owe us money. Of course, a guy like you probably owes a lot of people money — your friends, maybe even your parents. Stop being a freeloader and register DOOM. Call us now at 1-800-IDGAMES. We can help!"
— Doom ENDOOM screen
— Every monster, at any given time.