Funny / Duke Nukem 3D

• Let it be known that Duke is a man of his word. When he tells the Overlord that he'll rip his head off and shit down his neck, he does exactly that in the closing cutscene, even pulling out a newspaper to read as he does his business... all while whistling his own theme tune, "Grab Bag"!
• In the Mirage Barrage level from the 20th Anniversary World Tour:
  Duke: Why so serious, Sam?
• A classic: "Your face, your ass; what's the difference?"
• In some levels, you can interact electric sockets, taking shock and little damage. If your HP reaches 0 while doing this? You explode into bloody mess.
• Earlier versions of the game allowed you to use Duke's left-leg Mighty Foot and his unarmed right-leg kick at the same time. The result is that it looks like Duke is running around killing aliens with That Russian Squat Dance (or, if you prefer, Liu Kang's bicycle kick)
  • And a common joke about it is that he uses his "third leg" to support himself for those kicks.