Unfortunately GOG don't provide Linux/OSX versions of Doom 3 despite the source code being made freely available several years ago (not even in an unofficial/unsupported capacity)

There's two main source code projects:
> dhewm3 is the enhanced source code release of Doom 3 (vanilla)
> RBDOOM-3-BFG is the enhanced source code release of Doom 3 BFG edition.

Annoyingly game data taken from the BFG edition can't be used with dhewm as the file format has changed.
Opinion on which edition is best is divided.
The BFG edition is a lot brighter than the vanilla game plus the quick flashlight has no drawbacks hence the game is somewhat easier and less creepy over all. Not how ID intended.
In fairness there's some nice technical improvements like the non-stretched GUI + videos, faster loading times, extra graphical effects, etc.

I've uploaded the required files for dhewm3 since it's unacceptable to have to purchase the game twice on two platforms (particularly STEAM). It's also non-nonsensical to not have the choice of which version to use and on what platform to run it.

dhewm pak (.pk4) files
The game files match the md5sums on this page. The paranoid are welcome to check =)

It's simple for Windows users - binaries here and the game files above.

Linux users can either compile their own binary following the instructions on github.
Or install a package from their distribution's repositories which may be easier i.e:
> Arch,
> Ubuntu, etc
> You can also try using my compiled binaries (x86-64, Arch Linux, Phenom x4 955 [Family 10h/K10])
> This not might work due to compiler optimizations and/or other differences.
> In either case - you need to install all the required libraries listed on the github page.

Extract the game data archives. Don't alter the data structure. Place the binaries in the root game folder.
Resurrection of Evil can be loaded through the MOD option in the main menu.
Linux users will likely have to use chmod +x on the binaries in order to grant executable permissions.

If the game folder looks like the attached picture - it should work!

dhewm3 Screenshots
RBDoom3 Screenshots

Balls made of solid brass.

All the $5USD/etc. sales id/Bethesda loses out on by not just simply allowing GOG to also sell the vanilla release of 3 + the expansions is their own fault... I guess.

Yeah, GOG should bring the old version here, too. I WOULD pay an extra buck for it, if Bethesda/ID Soft wants money for it.

Well you can also use Classic RBDoom 3 BFG a even more advanced version of the original RBDoom 3 BFG

I second this since the original RBDoom3BFG hasn't been updated in years and development from main team has halted a few years ago while Classic RBDoom3BFG has been helping bring back old features from the original Doom 3 into BFG Edition.

EDIT: There's also a newer Doom 3 source port called fhDoom for those that are interested, and it seems to work with the Redux mod from my experience.

• https://github.com/eXistence/fhDOOM/releases