Actually, you are referring to two different series.
Note: The number of levels listed for Descent may be incorrect.
The start of the Descent series, Descent, released in 1995, was the first true 360 degree First Person Shooter. It not only had the X and Y axes for movement, but also introduced a vertical component, the Z axis. This allowed for forward and backward movement, vertical and horizontal sliding, pitching, yawing, and rolling. The game required 6 axes for full control, which could be supplied with a joystick with twist functionality, a hat switch, and a throttle.
I found youtube links for the intro and outro of Descent 2, posted here.
Intro: [ame]http://www.youtube.com/watch?v=KQCLZjyg07M[/ame]
Outro: [ame]http://www.youtube.com/watch?v=fTZuxGAUbro[/ame]
Trailer: [ame]http://www.youtube.com/watch?v=-5Tl4s1uu28[/ame]
There is a modification to Descent 2, called Descent XL, which allows you to play it on Windows XP. link:
http://www.descent2.de/d2x.html
The story of the game is this:
The PTMC, Post Terran Mining Corporation, had developed a series of mines throughout the Sol System. Robots mined and refined the minerals. According to Samuel Dravis, Director of the PTMC, the robots in the mines had gone berserk and had completely taken over the mines. All contact with the mines had been lost. You were tasked with destroying the central reactor of each mine and escaping, while rescuing any hostages in the mine. You were given a Pyro-GX Zero-G fighter for this task.
You started at the beginning of the mine, and had to fight your way through hordes of robotic enemies to reach the reactor. You had to collect keys to unlock doors in your way, color-coded Blue, Yellow, and Red. Your weapons were 4 levels of basic lasers, a vulcan cannon, spread pulse cannon, plasma, and Fusion, which fired purple bolts which penetrated any robots in their path, enabling you to annihilate entire corridors of enemies. Secondary weapons were basic concussion missiles, homing, proximity mines, dropped from your ship and exploding on contact with anything, Smart missiles, which released a cloud of homing plasma that swarmed towards the nearest target, and Mega missiles, which were very powerful. Once you destroyed the reactor, you were given a fixed time limit, varying with difficulty level, to find the exit and escape the mine. Descent had 30 levels, plus 6 secret levels.
Descent 2 carried you beyond the Sol System into interstellar space. The mission objectives did not change for this sequel. It had vastly improved graphics, AI including thief and sniper bots, and a Guidebot, which guided you to objectives. The weapon list for Descent II was greatly expanded. A list can be found at
http://www.r1ch.net/old/descent/weapons.htm.
Descent 3 did away with the old 'destroy the reactor and escape' system, replacing it with new mission specific objectives.
The basic premise of Descent 3 follows: Samuel Dravis betrayed the Material Defender, you, at the end of Descent II, crippling your ship and leaving you to die in a remote star system. A group of researchers with the Red Acropolis Research Facility rescued you and asked you to help them prove that Dravis was a traitor. A good review for Descent 3 can be found at gamespot,
http://www.gamespot.com/pc/action/descent3/index.html.
I was getting a bit tired at this point, so I will just provide links to gamespot's reviews of Freespace and Freespace II.
Freespace:
http://www.gamespot.com/pc/sim/descentfreespacethegw/review.html
Freespace 2:
http://www.gamespot.com/pc/sim/freespace2/review.html