My friend gogo discovered a Duke Nukem 2 (Version y1.4 beta) prototype on a ibm-wgam-wbiz-collection on web archive in ibm #145 tape, but it is unclear whether it is genuine or not. The password to play the game is superman

The oldest possible known build date in the files is September 18 1993. Also the build was known as Duke Nukem 2: Disposable Hero in NFO file. This is really late build of the game almost to final version with minor differences. Based on this NFO file by EXCRETION could suggest this might of been first Duke game ever leaked in history. Then got lost to time and resurfaced until now.

Also some cheat codes got uncovered by Frenkel Ommetje. Duke Nukem 2 beta cheats:

N+U+K full health and items

G+O+D+Enter God mode

When the God mode message is shown press: W warp to level R restart level F choose a weapon K change skill level

I will provide updates if anything else comes up and once I have more information. - ZNukem