I remember mostly playing the port of this to the PS1, which had a fully animated opening cut scene. When I got the PC port like fifteen years later at a Goodwill, I was disappointed to see that that was a Playstation exclusive.
Descent is good, but I do think the series peaked with Descent II, if for no other reason than the rocking soundtrack. Very awesome, cool, industrial rock; I used to put the game CD in my car to listen to it since it was Red Book audio.
Yes, Descent II OST is on a totally different level compared to the MIDI-only Descent I soundtrack. And by famous musicians to boot - like Type O Negative and Ogre of Skinny Puppy, who created my favorite "Glut" and "Ratzez" tracks. It was the time when games became big enough to bring popular musicians aboard for the soundtrack, Quake with Trent Reznor being a perfect example.
Also, the series was followed by Descent Freespace I/II, leaving a significant impact on the genre of space shooters. Though there are completely different games that have nothing to do with the original series.
That Descent II map editor was a top level utility for making some super creative levels.