Dark Forces is one of my favorite first person shooter of all time, thanks to playing it as a kid, and spending dozens of hours with it.
It's the first FPS in the Star Wars universe, featuring Kyle Katarn an Imperial officer turned mercenary who did countless job for the Rebels. He did stole the plans to the first Death Star, no matter what Disney did to this universe.
While from the outside it looks like the game uses the Doom engine or the Build engine, but LucasArts developed its own engine, which they later used in Outlaws too.
The nice midi music with all the well known Star Wars music adds to the atmosphere, while shooting countless stormtroopers is always fun.
Currently the game runs from DosBox, and you can buy it both from GOG and Steam. I use the GOG version as it has a setup for Linux.
After the DarkXL source port was abandoned, a new hope emerged in The Force Engine, which aims to have support for Dark Forces and Outlaws, but also mods.
Dark Forces with mouse look, crosshair and modern controls
If you want to play the game with modern control scheme (WASD) and mouse look, take a look at this guide: Modern Dark Forces Mouselook, KeyBinds and Crosshair Guide. It works for me under Linux. It's a simple .exe file that I managed to run with the provided DosBox.
I openned up the zip file and extracted the DFORCEDH.EXE file to the data directory, where your setup.exe and dark.exe are.
First: I started Dosbox, from the dosbox directory where I installed the game, with the the provided dosbox_DF.conf file.
Second: Inside DosBox I mounted up the data folder as C drive. Changed to C, then run DFORCEDH.EXE
mount C / the / place / where /your /darkforces /data /directory is c: DFORCEDH.EXE
Third: From this point you have 3 options. One is the recommended which tweeks your controls modern FPS style with crosshair and mouse look. The second is sets mouse look and crosshair, and lets you modify the keyboard. The 3rd one lets you set up everything manually.
The game works really well even with the default option, I like the crosshair, and while mouse look is weird for me at first, since I never played the game it like that, it definitely adds to the enjoyment of the game.