Source port

From Duke Nukem Wiki

Source Ports are versions of a game that have been modified to allow it to run on a different platform. For Duke Nukem 3D, a number of source ports are available to make the game compatible with modern OSes, most commonly Windows.

• icculus.org/duke3d – Icculus' port to BeOS/FreeBSD/Linux/Mac OS X/Solaris/Windows/Other.
• JFDuke3D – JFDuke3D, by JonoF. Port to Windows/Linux/Other.
• Duke3d_w32 – Rancidmeat port to Windows.
• xDuke – xDuke, a port to Windows. Commonly used to play Netgames.
• EDuke32 – EDuke32, a port to Windows/Linux/x86_64/Mac OS X. Most actively updated and advanced port.

Notice none of these ports will run by themselves; you must have actually purchased the game for some of the necessary files to play the game.