Ken's Labyrinth was developed by Ken Silverman and Andrew Cotter in 1992 (development started 1992-06-16, v1.0 released 1993-01-01) and originally distributed as shareware (5 levels free as in beer, the full 27 level game (v1.1, released 1993-01-16) available for $25). Version 2.0 (with improved art by Mikko Iho and many other improvements) was released 1993-03-21 as the new shareware version (10 levels) through Epic Megagames. Version 2.1, the new registered version (30 levels) was released 1993-06-22 and sold by Epic Megagames for $30.
The registered version (v2.1) of Ken's Labyrinth was released as freeware 1999-11-16 by Ken Silverman (with permission from Epic Megagames). Later, 2001-07-01, Ken released the source code to v2.1. The code is licensed under Ken's own license.
Based on the source Ken released in 2001, I wrote a port called LAB3D/SDL, which was initially released 2002-08-26. LAB3D/SDL should run on most systems with OpenGL; I release Windows (9x/NT/XP) and Linux i386 binaries myself, and the source code (also available) compiles and runs on many other Unix-like systems (e.g. FreeBSD and Solaris). I haven't tried compiling it on OS X, though. LAB3D/SDL features high-resolution OpenGL graphics, Adlib emulation (for correct playback of the music) and support for all four publicly released versions of Ken's Labyrinth. LAB3D/SDL is under the same license as Ken's source code release.
The "OpenGL version" of Ken's Labyrinth on Abandonia is LAB3D/SDL v2.32 (the latest version) with the Ken's Labyrinth 2.1 (latest registered version) data files compiled for Windows 9x/NT/XP.
Ken's Labyrinth
LAB3D/SDL