This beta was released by 3D Realms in 1997 to celebrate one-year anniversary of its immense hit Duke Nukem 3D.

Most likely however, the release was to prove that the game had in fact been under development for over 2 years before its release in 1996. If anything, the practical values of this "game" show you the development process of how one progresses from coding from scratch to a blockbuster game. See how lame Duke used to be before he got his break :)