Duke Nukem 3D is a first-person shooter computer game developed by 3D Realms and published by Apogee Software. It was released on January 29, 1996. Duke Nukem 3D features the adventures of Duke Nukem, a character that appeared in earlier platform games by Apogee. These were Duke Nukem and Duke Nukem II. Taking on the role of Duke Nukem, players must fight through 28 levels spread over three chapters. (A commercial upgrade later added a fourth episode of 11 additional levels.)
As usual for a first-person shooter, players encounter a whole host of different enemies and can engage them with a range of weaponry. As well as killing aliens to free the Earth, players must also solve puzzles to progress through the various levels. Some puzzles allow access to extra, hidden levels.
Codes
Enter these codes during gameplay. These codes cannot be used when the game setting is on "Damn, I'm Good!".
Dnitems - Adds all items, all keys and max body armor
dninventory - Adds all items, max body armor
dnstuff - Adds all items, weapons, keys, ammo and gives max armor
dnkeys - Adds all keys to inventory (Red, Yellow and Blue)
dnweapons - Adds all weapons and gives maximum ammo
dnhyper - Adds Night Vision Goggles and Steroids to Inventory, uses Steroids
dnskillX - Change to skilll level X (1-4), restarts level
dnview - Changes to 3rd-Person View
dncoords - Displays current coordinates, viewing position and other information
dndebug - Displays debug information (upper left corner)
dnshowmap - Shows entire map of level (press the map key)
dnrate - shows the framerate
dncashman - Throw some money when the "open" key is pressed.
Dnmonsters - Toggle monsters on / off
dnclip - Toggles clipping (walk through walls)
dnkroz - Toggles God Mode (Invincibility), Gives Jetpack (unlimited while cheat is on)
dncornholio - Toggles God Mode (Invincibility), Gives Jetpack (unlimited while cheat is on)
dnunlock - Triggers all the doors, forcefields etc. in the level to be unlocked / locked (only works in the registered version)
dnscottyXYY - Warp to Episode X (1-4) Level YY
Glitches
Double Mighty Foot This is an extremely easy glitch to do, but only works in the original Duke Nukem 3D for DOS and variants.(Plutonium Pak, etc.) Simply select Weapon 1(Duke's Foot) then hold the Fire button. As you're doing this, hold down the Mighty Foot button as well. Duke is now kicking 1.5 times per kick! Not only that, but he's doing so using both his left and right feet at the same time. How gravity defying.
God Mode in Damn, I'm Good To use this, you must first activate god mode in any difficulty level except Damn, I'm good. After that, wrap to a boss and kill it. Once you have done that, start a new game on Damn, I'm good and you'll be in god mode. This works until you go to a lower difficulty level and deactivate it or quit the game entirely.
Here's some gameplay footage from the game's first episode, level 1: