The sequel to Descent: Freespace was developed by Volition and published by Interplay in 1999. Like the original, it is a space combat simulation (wherein various types of spaceborn craft attempt to blow each other into little bits).
A note about plot: because this is the sequel to a game, no discussion about its plot is possible without providing spoilers about the end of the first game. For that reason, all discussion about the game's plot is contained later in this writeup, between the horizontal rules.
The Freespace games have always revolved around the ships in them. As the player, you pilot various sorts of fighter craft: bombers, interceptors, space-superiority fighters, and so forth. Often, missions will involve you defending or attacking (or both) large capital ships, ranging in size from small frigates to massive flagships 12 km in length. These ships are extremely heavily armed and armored. All of the armarments from the first game make an appearance: blasters, missiles, and so forth. However, the capital ships have several new weapons in this second chapter, mostly designed to ease the task of taking out fighters and other capital ships. To kill the capital ships, there exist massive beam weapons, which can destroy these large ships in mere minutes (and pity the poor fighter that stumbles into the crossfire; instant roasted pilot). There are also smaller, faster-tracking versions of these beams, which exist for the express purpose of blasting the small, fast-moving fighters. In addition to these beam weapons, capital ships have flak cannons, which shoot hundreds of tiny (innacurate) exploding particles, which usually don't provide any serious threat to a ship, but can slowly erode its shields.
The Shivans (the evil alien species from the first game which, yes, makes a reappearance here) are more powerful than ever. In the first game, they had the toughest, most agile, and most powerful ships in the game. They still do in this game... which means even more when you consider that every ship you use in this game is better in these respects than the best ships in the last game (making the Shivan ships godlike in their abilities to run circles around you). The fact that everything you use is faster and so forth than everything from the last game is a very nice touch (the games are 32 years apart, and the intervening technological changes have advanced ships greatly). Almost all of the ships from the first game make a re-appearance, in the form of fairly crappy older ships that don't stand a chance against anything newer.
The physics of the game (being identical to the original's) are far from realistic, and seem meant to simply transfer the mechanics of a conventional aircraft dogfight into deep space, where there is no up or down. The ships can fly forwards, and can turn. When they turn, they seem to be able to change the direction of their movement effortlessly, which seems to fly in the face of conservation of momentum. An interesting contrast is Independence War 2, which offers a realistic physics model (you can accelerate to almost any speed, but then you have to spend the time to slow back down; if you want to change directions, you have to reduce your velocity on that axis first). However, all of this is just the developers choosing gameplay over realism, which is a perfectly good excuse (I heartily approve).
Like the first game, you start piloting a fairly average ship and the worst weapons in the game. As the game progresses you are transferred to different units, which each use different types of ships (for example, a bomber unit or an interceptor unit.), and gain access to more and more powerful weaponry. One or two missions let you use one of the unique ships in the game. (These include a lightly armed stealth ship or a stolen Shivan ship.)
This is the bit where I go over the plot (which is actually fairly interesting). This means giving away the ending to Freespace, so if you don't want that to happen, I recommend you skip to the next horizontal rule.
The opening movie to the game opens on a battle from the first game, where the invulnerable Shivan destroyer Lucifer is kicking the crap out of some GTA (humans; the good guys) and Vasudan (the other, mostly friendly alien race) ships. This starts to follow a single ship, which is shot down, to crash on the planet all this is happening in the orbit of. After following this the game jumps 32 years into the future, and a bit of a monologue starts. In a nutshell, it talks about how Earth was cut off from the rest of humanity when the Lucifer was destroyed. See, faster-than-light travel is done by means of what I'll just call wormholes for the sake of brevity, and the Lucifer was destroyed whilst in transit to Earth; the resulting explosion destroyed the only wormhole out of the Sol system. The monologue goes on to talk about how humanity is starting to push forward after being cut off from its homeworld, and it ends on a shot of a really goddamn large human ship, with a sizable battle group escorting it.
The first few missions involve you, a pilot for the GTVA (the alliance between humans and Vasudans), fighting this anti-Vasudan rebellion that has popped up and taken a few star systems. This goes on for a while until, the horror!, the enigmatic Shivans pop up in an uninhabited backwater system and destroy some stuff. The meat of the game is about the GTVA's efforts to fight the Shivans; the leader of the rebel movement and his motivations (which aren't what you think); the Really Big Ship seen in the intro; and where the Shivans actually came from. I'd place the quality of this sci fi plot as somewhere from above average to pretty good. Its main strength is that it presents the story right in the missions, in the middle of the action (sure, you the player seem to fight in every major military action of the war, but this can be forgiven). This is also its weakness, as there's very little room for little things like characters.
All told, this is a wonderful game. The graphics are very nice, and have aged quite well in the past few years (for reference, the recommended minimum requirement is a 266 MHz Pentium). The sound is perfect, too, and the voice acting is decent. A joystick is a must, but nothing fancy is required; even a decent two-button 'stick would serve you well. The one thing that stands in many people's way with this type of game is the control scheme, which is fairly complicated. If you're able to play a MechWarrior game, you should be fine here. (All you need to keep track of are your shields, weapons, targeting controls, energy balance, and, oh yeah, flying the ship... okay, that's a lot.) The game is very stable, with nary a crash or stall. The free multiplayer service leaves something to be desired, as the game is slow to the point of being unplayable (not to mention the chronic lack of players). The single player game, however, is extremely lengthy and offers a great deal of enjoyment on its own. If you see this sitting on a shelf, I recommend picking it up.