Descent: FreeSpace was well-received as a single-player space simulation that integrated all the desired features of its genre, from competent AI wingmen, to the presence of large capital ships that dwarf the fighters piloted by the player and explode spectacularly when destroyed.

In both modes, the player controls their craft and other commands through either a joystick, or a keyboard (either on its own or with a mouse),[3][4] and primarily view the game's environments from the first-person perspective of a cockpit within a starfighter.

In single-player missions, the HUD also displays the condition of any wingmen the player has supporting them, represented by a circle that changes to a darker colour when the craft has taken critical damage and becomes an outline when the wingman has either departed or be killed in action, along with an "Escort" list that keeps track of notable vessels that the player either must escort or destroy, the number next to the vessel's name indicating how much hull integrity they have.

[10] In addition to the game's standard campaign, the player may also make their own missions and campaigns through the use of a free editor bundled with the game - the FreeSpace Editor (FRED for short) - which allows players to have the same capabilities as Volition's development team in making their own missions, with the ability to import personal audio and 3D animation files.

[14] By the time the story begins, this war has entered its fourteenth year, as a third species, dubbed Shivans, makes an unprovoked attack on the Terran system of Ross 128.

The player, acting as a new Terran pilot in the GTA, is initially involved in the conflict with the PVE before the fights focus on the new species' arrival and subsequent assaults.

A fourth race, dubbed "The Ancients", is not shown in the game but referenced during the single-player story as having lived thousands of years ago and having once held an empire in the systems controlled by the Vasudans and Terrans, before they were driven to extinction by the Shivans.

Despite the ceasefire coming into effect after the operation, a Vasudan death cult called "The Hammer of Light" (HoL), who worship the Shivans, launches attacks against both GTA and PVE forces.

To the shock of the new alliance, the Lucifer is found to possess a powerful shield system that makes it immune to all conventional weaponry, thus allowing the Shivans to spearhead its invasion towards the homeworlds of the Vasudans and Terrans.

Investigating this, the alliance uncover remnants of a long-extinct alien civilisation on the planet, dubbed "the Ancients", who had amassed a vast galactic empire several thousands of years ago, before the Shivans wiped them out.

Armed with this knowledge, the alliance launches a desperate assault to stop the super-destroyer as it prepares to enter the jump node to Sol from the Delta Serpentis system.

[17][18][19] The setting of the expansion takes place after the events of the "Great War", with both the GTA and PVE working together to rebuild their systems and deal with the remnants of the Shivan Armada.

Following the end of the "Great War", both the GTA and the PVE attempt to focus on the rebuilding of their systems and dealing with the remnants of the Shivan forces, although the alliance between them is in a fragile state.

In order to ensure the alliance does not collapse, GTA command assigns the GTI to the task of preserving it, while assisting in protecting valuable research projects and dealing with the remaining Shivan forces.

[20] During engagements, a science vessel that had been recorded as being officially destroyed during the war with the Shivans, the Einstein, turns up during an operation to protect Vasudan craft.

Although the crew escape before the vessel is destroyed, suspicions surrounding the science vessel's appearance are aroused, when recovery of the ship's escapes pods is compounded by confusion in communications that lead to two of the GTI's destroyers, the Krios and the Repulse, arriving and claiming to be there to recover the pods; the latter later proves they were assigned to this responsibility.

As the GTA and PVE launch further attacks on the Shivans, it is quickly discovered that what is left is unorganised, leading the alliance to co-ordinate a full invasion of their main strongholds, as other systems they occupied slowly return under Terran and Vasudan control.

[21] The pilots sent out by the Krios during the final fight with the Shivans, return early, arriving in time to discover the treason and alert GTA command.

Investigations into its origins reveals that the GTI had known about the Shivans much earlier than the GTA and PVE during the "Great War", and that the Einstein was officially declared as destroyed in order to observe the species without interference.

Their rebellion was designed in order to overthrow the GTA government and dissolve the treaty with the Vasudans; the Krios destruction was because the head of Special Operations had unearthed the plot after managing to get details from some of the crew of the Einstein.

Themes from the fiction of Star Wars, Space: Above and Beyond, and Ender's Game form a part in shaping the background and story of the FreeSpace world.

[25] Mike Kulas, who had worked on several versions of Flight Simulator and Descent, brought his experience into the game's artificial intelligence (AI).

[35] This was part of their agreement with Interplay for the latter's purchase of the rights to Descent, and Apogee decided to release FreeSpace as shareware, with themselves as the merchant of the registered version.

Interplay hired science-fiction writers such as Fred Saberhagen, Simon Hawke, and Jeff Grubb to write weekly FreeSpace stories for two months.

PC Data, which tracked computer game sales in the United States, reported that Descent: FreeSpace earned nearly $4 million and sold around 100,000 copies by October 1999.

[51] Next Generation reviewed the PC version of the game, rating it four stars out of five, and stated that "overall, despite a few minor lapses, Descent Freespace: The Great War is definitely a keeper.

[50] Descent: FreeSpace received generally good reviews following its launch, with PC Gamer UK placing it 20th in its 1999 Top 100 Awards.

[7][8][53] Despite the differences between them, all reviewers unanimously agreed that the explosions effects in the game, including the many small details of the capital ships upon breaking up, were the most impressive they had seen (at the time).

[60] PC Gamer US nominated it as the year's best action game, and its editors wrote that "Freespace came from nowhere to wrest the 3D space combat crown from the Wing Commander series with style".