A sequel to Volition Inc.'s FreeSpace. It's basically more of the same, but does feature a few new treats (plus better graphics). The essense of the game is that you dogfight nasty aliens in outer space, ala Wing Commander and countless other titles.
If you thought the Orion class ships in FreeSpace were large, you'll be amazed by some of the new capital ships, both friend and enemy. These ships can fire beam weapons; essentially big lasers. They fire the larger ones only at each other, which is good, because you, in your tiny little fighter, will often be killed almost instantly if you're hit. But they also have smaller versions of the beams (and also flak guns) just for people like you. These can make your life very hard, or very nice, depending on who's at the control of them. I've often escaped certain death in situations where my entire team has been killed off, I'm out of missles, and I'm being attacked by half a dozen (or more!) enemy fighters, simply by racing as fast as I could to the vicinity of a large (friendly!) ship. They will chase you right up until the end, when the larger ship starts shooting them full of holes.
You spend a great deal of time fighting in nebulas, which can make your life hard by cutting visibility and messing up your computer (from the EM radiation). This also adds a lot of suspense; you're creeping through a dense fog, wondering when the shit will hit the fan, and then, WHAM, all of a sudden you're less than 100 meters from a giant enemy battleship.
There are also a lot of nice new ships and weapons for you to play with, including an updated version of the Hercules assault fighter, and another heavy fighter that looks like a big housefly. And a bomb that makes the Tsunami and Harbringer bombs from the first game look like firecrackers.