id-Software/DOOM — reverse-engineered prompt

I want a working, easy to run version of the original open source DOOM codebase. Please get it building cleanly on a modern Linux setup, and if it makes sense, make the project portable enough that it would not be hard to bring to other systems later. Keep the classic game feel and behavior intact, this should still feel like real DOOM, not a remake.

The app should clearly let me point it at real DOOM game data, since I know the source does not include that. Make the startup flow simple, with clear instructions for how to build, launch, and supply the game files. If there are obvious cleanup fixes needed because the code is old, go ahead and do them so it is stable and actually playable.

If you have time for a couple small extras, add optional quality of life improvements like better input handling or a few rendering experiments, but only if they do not break the original game. Look up current docs online if you need to.