I wasn't always acquainted with the hybrid Shooter/RPG-elements/Sci-fi genre. I discovered Deus Ex and System Shock, very late into the party. I am more interested in their old predecessors, from the time that the genre hadn't been established and well defined, yet.

I would like to know good quality, solid titles, like Strife offered here on GOG (already in my wishlist), Cybermage (which i beat recently), this kind of games. In anticipation for the summer sales, i would like to get me some Good Old stuff. The older the title, the better.

Guess that Ultima Underworld is the father of them all. Same goes for System Shock 1 which came in its wake.
Deus Ex tho is the diety of them all.)

Thanks! I have played Arx Fatalis, which is said to be the spiritual successor of Ultima Underworld and i love it! Guess it's time to try its grandpa, then!

I have both Deus Ex and System Shock (i need an extra push to finish them, though, shame on me!)

Obviously it's a different genre, but I'd go as far to suggest TES II Daggerfall.

It's full of dungeons (even for an RPG), that are very identical to strife.

Also the game world is proceduraly generated (and this game was released back in the 90s, go figure) so it has insane replay value, if you can stomach the graphics (but since you liked strife I don't think that's a problem).

Plus, you can get it for free on bethesda's website ( https://cdnstatic.bethsoft.com/elderscrolls.com/assets/files/tes/extras/DFInstall.zip ) or on gog as a free goodie by buying any game developed by bethesda.

EDIT: I have no idea why the above paragraph is formatted like this. :(

There's also a project of remaking Daggerfall in unity ( https://www.dfworkshop.net/ ) and it's lovely!

Hey, thanks for the heads up! I already own this title on my library and shame on me, i never even knew! Will definitely check it out!

Exhumed/Powerslave is kinda similar as well, but without the shops and most of the NPC interaction. The console versions are more non-linear in structure and let you explore new parts of previous areas with the abilities you gain throughout, and there's some sequence breaking opportunities. They're also harder though as you can only save in-between levels (unless you emulate of course).

Though not exactly an fps/rpg, check out blade of agony (it's a free gzdoom total conversion mod based on wolfenstein with a central hub and sneaking). It really is great.

Also maybe check out In the shadows mod for quake, the dark mod (though it's a thief style game), the arx insanity mod, the arx end of sun mod for doom 3, stalker or vampire the masquerade bloodlines. Just search immersive sims on google (there are quite a few).