As venerable as this game's graphics look, many hail it as the progenitor of the 6DoF genre of games. Much like the original Elite game's fame as the first to bring 3D vector models and sandbox gameplay to the personal computer, Descent was a pioneer in its own right on several levels.
For starters, the only game that rivaled its level of controls complexity at the time of its release, it can be argued, was Mechwarrior 2. Pretty much every game before 1995 that involved first-person flight or movement were restricted to three axes (turn up-down, turn left-right, and move forward-back). The occasional lateral movement was included (slide left-rigth), and was far less common, but games such as Quake and Duke Nuke'Em come to mind. They might or might not include jumping, and crouching started getting introduced, but the physics of the world they took place in also limited their control schemes. Most space flight games of the age had no lateral movement either. The original elite had no slide left-right, but had roll instead. Each scheme had its own challenges, but never gave you all the options in a single package.
Then along comes Descent, a game with no gravity and no limits. You could turn up-down-left-right, you could slide up-down-left-right, you could move forward-back, you could roll, you could look behind you, and you could afterburner for short boosts. Not only that, but you could move in as many as three directions at once, and the speed benefits were additive, allowing you to perform what was then dubbed 'chording' for the greatest velocities. Triple-chording was tricky, took skill to get right, and was sometimes dangerous (running into walls or lava), especially in the middle of dogfighting. In the sense that EVE Online is the hardest MMO ever created by at least a couple orders of magnitude, Descent was harder than other first-person shooters by an equivalent amount.
It was also, along with Quake and Duke, one of the first few shooters you could play against other players. All three originally supported only IPX protocols instead of TCP for network play, which meant you could only play against others on the same LAN, but services later started to appear (such as KaliDOS, Kali95, and Khan) that would do IPX-to-TCP translation and allow you to play against others across the internet through dial-up connections, ISDN, or eventually cable modems. I have countless memories of LANfests and ladder matches in the early days of Descent and Descent 2 that, even to this day, have no equal because of Descent's no-direction-is-safe design.
6DoF games have traditionally been a niche for the hardcore gamer, with very few other games in the genre released. The original Descent had two more games released, of course, and there was also a direct competitor launched later called Forsaken which received decent support on its own (see ProjectX for details). Much later, Jumpgate Evolution had aspirations of becoming the king's successor (and would have succeeded) before it was cancelled. Not long ago, Miner Wars was released as an homage to this genre, but it fell short and was riddled with bugs. The most recent potential inheritor of the throne, according to documentation and videos I've seen thus far, may actually prove to be Elite: Dangerous, and this makes me a happy camper.
Regardless, Descent deserves a place in the history books as the grandfather to this playstyle all by itself. Even if you discount the control scheme and ridiculously tricky and hilariously awesome multiplayer in its heyday, other aspects shine that were uncommon as well. All of the original game takes place in the confined spaces of off-world mining facilities, with the layout of most of them painfully unfriendly to two-dimensional thinking. Since there was no gravity and the mine traversed deep into the structure of the asteroid or planetoid it was carved into, there was also no reason to limit the level's layout to traditional gravity-based constraints. It was a great deal easier to get lost if you weren't paying attention to all the options in all directions.
Lastly (at least among the aspects of the game that deserve special mention) was the lack of blood and gore. In an age where the amount of violence against living antagonists (whether NPCs or other players) was increasing exponentially, Descent was a nice alternative that gave parents a choice they could get behind instead of turning a blind eye to the scary biologicals of Quake or sexism and bloodied aliens of Duke.
Having typed this giant wall of text, you'd think acquiring a classic like Descent is a decision without flaws. What's worth of mention here is that this version is the original, and runs inside a DOSbox emulator. Because of this, combined with the fact that the game was coded from the ground up and tuned for much older hardware, before even the first 3DFX Voodoo cards came out, the original verison of Descent suffers from having some of its routines tied directly to the speed of the machine. The ability for certain missiles to track you, in particular, are greatly augmented by faster clock speeds. Whereas someone playing the game on a 486/33 machine back in 1995 could easily dodge deadly missiles with just a little practice, it's much harder now.
Leveraging DOSbox in order to play this game today also brings other problems which can be avoided. Two of the most well-known community efforts to resolve issues like those stated above are D1X-Rebirth (which endeavors to provide a fairly faithful recreation of the original) and D2X-XL (which has several features the original game doesn't, and lets you play both Descent 1 and Descent 2 inside the same engine), both of which are more than passing improvements to the DOSbox method. If they're better than this Steam product, then why purchase the Steam version, you might ask? Because they contain none of the copyrighted files necessary to play the original games. There are what's called .PIG and .HOG files located in the original game's installation directory which contain all the data for the game, such as textures, creature models, and level designs, that can legally only be obtained except through purchase of the game created by Interplay.
So I strongly encourage you to try this game as it was originally crafted, through the DOSbox method provided here, and if some part of the DOSbox experience or the performance or behaviors of the robots and weapons frustrates you, try leveraging the results of the community and follow the installation instructions of D1X-Rebirth or D2X-XL to give it another spin. One way or another, you'll get far more than your money's worth.