The Japanese version of the game removed the cigar from Duke Nukem's mouth on the box art.

In the French release of the game, the achievement "Fork the Pork" is called "T'as le Bonjour de Ryo" (Ryo says hello). In order to achieve this, the player must kill 6 pigcops with a forklift.

This achievement is a reference to the game "Shenmue", which sees the player take on the role of Ryo. The game featured a popular minigame that has the player driving a forklift.

Gamer Slash000 pre-ordered Duke Nukem Forever in 2001, and GameStop honored the pre-order when the game was released in 2011. Not only did he get his long awaited game, but Gearbox sent him a care package full of Duke Nukem Forever merchandise.

The talk show host of "Damn, It's Late", Johnny O'Lenoman, got his name by combining four popular talk show hosts names together. These being Johnny Carson, Conan O' Brien, Jay Leno and David Letterman.

Spoiler:During the game's ending, after the nuke explodes, the EDF logo is shown with a spinning globe. It zooms in and shows Duke was killed in the explosion. Duke then says "What kind of shit ending is that? I ain't dead, I'm coming back for more!" This is a reference to Call of Duty 4: Modern Warfare.

In the beginning of Duke Nukem's Titty City, one of the strippers asks you to get her a few things. One of the things she says to get Duke to help her is that there will be cake. Spoiler:Since the entire level is set in a dream and you do not see the cake any where in the level, the cake she is talking about is most likely not real. This is probably a reference to Portal's "The cake is a lie" meme.

When Duke admires himself in the mirror, he says many quotes. Some of them are:
"I'm bringing sexy back." refers to Justin's Timberlake song Sexy Back.
"Here's looking at you, kid." is a quote from the 1942 movie Casablanca.

At the level Forkstop, there is a barrel with a heart on it. You have to move it to the spot with a heart on the floor to get a trophy. When you put the barrel in the right place, you will see "Have some cake!" It's a reference to the game series Portal.

When Duke comes across a door that needed a red keycard to unlock, Duke responds with "Keycard? I don't need a fucking keycard." and opens the door with bare hands. This line makes fun of the previous Duke Nukem games where the player needed keycards to open most of the doors.

In chapter Duke's Titty City in the bathrooms, written on the wall is "They Live, We Sleep." This is a reference to They Live.
And right below this writing you can see Mr. Chad on the wall behind the toilet referring to the American popular culture expression that became popular during World War II "Kilroy was here".

When in front of a wooden barricade Duke says "A crowbar would come handy right now." This is a reference to Gordon's famous weapon from Half Life.

When you try to solve the puzzle with the valves, Duke says "I hate valve puzzles" referring to the famous game company "Valve".

The two Duke babes that are at the beginning of the game are named Mary and Kate Holsom. This is a reference to Mary-Kate Olsen.

There is a soldier cursing and complaining that he had to help his friend find his wife. This is a reference to Marcus Fenix from Gears of War.

In the chapter 'Las Vegas' Duke says "I'm from Las Vegas, and I say: kill'em all!" This is a reference to Starship Troopers.

When you are in the casino, at the point you turn tiny and come across a mouse, Duke will say, "Now that's what I call a rodent of unusual size." This is a reference to The Princess Bride.

Before going into the dam, after Duke talks to the General, Duke sings "America, fuck yeah!" This is a reference to Team America World Police.

In chapter 'Damn, I'm Good' you can defeat the boss Energy Leech with just 1 hit from the Ray Freeze gun.

At the chapter "Damn! it's Late" there is a moment that you walk back stage and encounter a dialogue between an actor and a director. This is a reference to Christian's Bale infamous freak-out toward his director during a movie scene shooting.

While in the casino, you see the numbers 4, 8, 15, 16, 23, and 42. It's a reference to the numbers from LOST.

Duke is offered power armor, but he refuses the armor saying "Power armor is for pussies." This is a reference to the Halo series. It should also be noted that Halo themed music is playing in the background during the scene.

In the Duke Dome chapter before fighting the boss, Duke says "you are one ugly motherfucker." This is a reference to the movie 'Predator'.

When opening the door to Queen Bitch, Duke says "You make me wish I had three guns." This is a reference to Total Recall movie, where a women with three breasts says "you're going to wish you had three hands." Queen Bitch also has three breasts.

When in the chapter Duke's Titty City, on the desk in the Employees Only room where the security camera is, there is a never-ending spinning top. This is a reference to Inception.

In chapter Titty City when Duke interacts with a phone, he hears "Tonight... You." This is a reference to Handbanana from Aqua Teen Hunger Force.

In Duke's Titty City, when you look in the mirror in the bathroom you can see the word "MURDER" reflected off the wall (as REDRUM) in the back. This is a reference to the movie The Shining.

In Duke's Titty City there is a message "Jenny 867-5309" scribbled on the wall. It is a reference to the song "867 5309 (Jenny)" by Tommy Tutone.

In the chapter "Damn, It's late," you will have to sign a book for a kid. This book (entitled "Why I'm So Great") is the same book that Duke was being interviewed about in Duke Nukem II.

Duke was originally going to have a sidekick in the form of a gay robot. This wasn't to make fun of gay people, but to add depth to Duke's character. The idea was scrapped during development because the robot had a tragic ending, and the developers felt that Duke was more about action than tragedy.

"'Sexuality is part of the Duke personality.' The head of Gearbox explained that the original idea behind the sidekick was 'to explore how Duke would relate to a peer that might have a different sexual orientation.'"

"Ultimately the robot was in a situation where for in order for victory against the aliens to be accomplished, the robot's inner workings "“ a nuclear generator "“ had to be sacrificed."

"Duke is all about having a good time. Do you want to pay $60 to feel like crap? No!"

At one point during the game you will be accompanied by a Private Jenkins. After he runs ahead of you, he will be killed by an alien spaceship, and Duke will say, "Dammit Leroy!" This is a reference to the popular YouTube video where Leroy Jenkins gets his clan killed in World of Warcraft after charging into a dungeon screaming his name.

During the first fight with an Assault Commander boss, Duke says, "I'm going to kill you old style!" This is a reference to the Youtube video Ventrilo Harassment where a Ventrilo user is harassed by someone with a Duke Nukem soundboard. The voice actor for Duke Nukem, John St. John, has mentioned in interviews that he has seen the Ventrillo Harassment video, which probably lead to the line being in the game.

"It's awesome"¦especially the Ventrillo Harassment! I LOVE that fans have used my voice to create some very funny videos and soundboards."

In the level 'the Hive,' you can find the dead body of Isaac Clarke from Dead Space. Once you find him, Duke will comment, "That's one dead space marine."

In the level Blown' the Dam, there is a long Stair way with barrels are bouncing down at the player. Duke will comment, "Where's a hammer when you need one?" on the way up. At the top, you will see a Pig and Duke will say, "Huh, I was expecting a Monkey." This is an obvious reference to Donkey Kong.