I don't know how Terminal Velocity landed on my family's PC in the mid-'90s, but I know I spent too much time playing it. We didn't even have the full game, just the shareware version which only included the first chapter, and I'm pretty sure I never actually bothered to reach the end of that chapter. I just liked flying the spaceship around.
An updated version called Terminal Velocity: Boosted Edition (opens in new tab) released today, and by contemporary standards, that first level I played so much of is barely a videogame: You fly around above an alien planet shooting enemy ships and tanks and buildings, collecting power-up orbs, and sometimes flying through tunnels. The flight model gives you a level of control that's close to Descent's, but you always have some forward momentum. There ain't much to it, but I still remember why I was so into it: the scale. It felt like you could fly through the first planet's mountain range forever. (The Steam page says there are "over 400,000 sq miles of terrain," for whatever that's worth.)
I was 10 years old and 3D graphics of any kind were exciting in 1995, so that mostly explains the fascination. Playing it again, though, I pine a little for that old sense of wonder. Terminal Velocity was my first "open world" game, sort of. All I ever found in my explorations were more power plants to shoot, but back then just the sense of freedom and the possibility of observing an interesting peak or valley kept me playing, even if the whole level is probably less complex than one of Kratos' eyelashes in a modern God of War game.
Boosted Edition makes some technical improvements for modern PCs, the biggest of which is an increased view distance, which I'm not sure I like. The fogginess of the original made it feel more mysterious, and now you can sometimes see enemy ships hovering in the distance, waiting for you to approach before their combat loop switches on. For the most part, though, it's the same Terminal Velocity I played over 25 years ago, which was originally published by 3D Realms and developed by Terminal Reality, (opens in new tab) the studio that went on to make BloodRayne. The Boosted Edition comes from Ziggurat Interactive.
I've skimmed a full Terminal Velocity playthrough on YouTube (opens in new tab), and there are some cool-looking bosses and levels beyond the first world—parts of it remind me a little of Devil Daggers. Oh, and the music: I listened to the theme from the first level (opens in new tab) so many times it's burned into my brain, so I can't be trusted to judge whether or not it's good, but I love it.
I'm not sure I recommend Terminal Velocity unless you also have some nostalgia for it, but if you do decide to play it, a couple words of advice. One, the Boosted Edition's mouse controls are a disaster for me: I can either make them absurdly sensitive so that my ship spins out of control, or so sluggish that I can barely turn. I eventually settled on using a mix of WASD and sluggish mouse control (using the "absolute" motion setting) to fly, which isn't so bad, so you might try that if you're having the same issue. And two, if you keep bouncing off the entrance to the tunnel, that's because you're trying to fly into the exit. I don't know how long it took 10-year-old me to figure that out, but it was a while.