Recently finished Dark Forces II: Jedi Knight and Dark Forces II: Jedi Knight - Mysteries of the Sith on my Ayn Thor, thanks to the Android port of OpenJKDF2. I've played it with some graphical mods, but not the full texture replacement pack (because it didn't work properly) on the Android port. I've heard good things about the level design so I wanted to give them a try. They came out before SiN/Half-Life at a time where full-3D FPS were getting common but still mostly had old-style levels that were more designed for gameplay than as functional environments. And it really shows. The first game has credible environments that look a bit like actual places (with obviously limited polycount) but they really feel like they were first thought of as game levels, not as places. The second game shifts a bit away with some levels that feel more like places with enemies added inside and it doesn't feel as fun. Both games do love to play with verticality in a way that's not very common in FPSes. They also have secret-hunts common in early FPSes and an extra incentive since finding all secrets in a level leads to extra force power points.
Which brings me to another aspect: jedi stuff. There's a lightsaber that's a bit rough and best left for situations where you can't use other guns, though by the end of MotS the game forces you to rely only on it and I started enjoying it. Still, it would be much improved in the later Jedi Outcast/Jedi Academy games. Same for the force powers. In JK, I mostly used them when I had to, except at the end of the game where some of them get overpowered. In MotS there are more situations where you have to use them and an increase in difficulty that force you rely on them more. Once again, they got much better in JO/JA.
Jedi Knight has cheesy late 90s FMV cutscenes, which I always appreciate. MotS has in-engine cutscenes that manage to look less good than the actual game. I mostly enjoyed both games, though MotS was a bit more uneven and had a few frustrating levels that had me look at a walkthrough to figure out how to solve a puzzle. It's also generally much more difficult. I don't think I'll remember them fondly or even for very long. They have aged, they aren't bad but if you're looking for fun FPSes you probably have better options.