About
Commander Keen is a series of side-scrolling platform games developed primarily by id Software, with six main MS-DOS episodes released in 1990-1991 following the young genius Billy Blaze as he defends Earth using his homemade spaceship, rayguns, and pogo stick. Reconstructed Commander Keen 4-6 is an unofficial source-code reconstruction of the original Keen 4-6 (version 1.4/1.5 EGA and CGA releases), built primarily from the Catacomb 3-D source code, with text-view code based on Wolfenstein 3-D and game/actor code loosely based on Keen Dreams. It targets DOS and requires the original Keen 4, 5, and 6 executables, from which patch scripts extract the needed data before the code can be compiled with Borland C++.
How it differs from the original
Unlike an official id Software release, this is a fan reconstruction pieced together from other id Engine source releases (Catacomb 3-D, Wolfenstein 3-D, Keen Dreams) rather than the lost original Keen 4-6 source code itself.
Getting started
Building requires Borland C++ 2.0-3.1 run inside DOSBox, plus the original Keen 4-6 executables, from which patch scripts (CKPatch or K1n9_Duk3's Patching Utility) extract the needed data files before the project's batch scripts compile the code.