Dook Nookim has been pushing it even further, to run on 286 and even 8086 machines. And monochrome fixed-font MDA graphics. And Amiga 500.

Personally, having utterly failed to get the game running on IBM 5150, I can attest this is all high witchcraft. If only to unfuck Open Watcom's cross-platform compiler flags.

During development, DOS I/Os were written by id Software. This became the commercial release of DOOM. But that version could not be open sourced in 1997 because it relied on a proprietary sound library called DMX.

If I had a nickel for every time open-sourcing a Doom sequel's audio code caused legal headaches, I would have two nickels.