Doom - In the chapel you find a "Doomed" space marine
Shawshank Redemption - Passage behind poster
Hunt for Red October - USS Dallas (submarine)
"Jenny" by Tommy Tutone - 867-5309 (next to the urinal in E1L1)
Rise of the Triad - Hanging monk in the chapel
Army of Darkness - Quotes like "Come get some"
Predator - Boss says "Who the hell are you?"
Total Recall - Holoduke and Alien handprint switch
O.J. Simpson - The TV screen in the bar and the billboard that says "Innocent?"
Aliens - The woman stuck in slime
Anarchy - The anarchy symbol in the hidden apartment
Commander Keen - "Dopefish lives"
Cheating - All those messages like "How did you get here?" and "You're not supposed to be here."
Caddy Shack - Baby Ruth in the bottom of the pool of "HOTEL HELL"
Star Wars: The Empire Strikes Back - Luke Skywalker hanging in ice in the cave in E2L7.
The Terminator - Terminator in E3L11. "Terminated!"
Indiana Jones - Hanging Indiana in E3L8. "So we meet again, Doctor Jones!"
2001: A Space Odyssey - In E2L8 you see the Tycho Monolith from the beginning of 2001, and the accompanying music.
Quake - In E3L4 there is an EarthQuake. Duke says, "I ain't afraid of no Quake!" Great pun!
"Car 54, where are you?!" - The tipped over police car 54 in E3L11
***Note*** There are some supposed references out there that I don't really think are references, so this list has been trimmed to show that and may not have all the references that other pages have.
If you have any comments, suggestions, or know where I can link to some levels...