The story centers around the role of a lone human pilot of the Galactic Terran Alliance (GTA) who becomes the unlikely protagonist and hero. Players are taken through a gameplay tutorial before they are thrust into the middle of patrol missions for an ongoing conflict with an alien enemy known as the Parliamentary Vasudan Empire. As the war progresses through several missions, a new, unexpected and frighteningly superior enemy called the Shivans emerge and lay waste to combatants on both sides of the war. Confronted with the grim reality of assured obliteration at the hands of this new foe separately, Terrans and Vasudans are forced to join forces out of hopes that the collective strength of their new alliance will help them stop the advance of the Shivan armada.
As the plot unfolds, players embark upon several intense missions under the new alliance to attempt to find ways to overcome the Shivan technological advantage that keeps allied forces from either targeting or damaging Shivan vessels. While fending off the Vasudan splinter group 'Hammer of Light' along the way, the player becomes the key to the capture of a Shivan vessel through which weaknesses can be found. The captured vessel reveals the true threat: a Shivan vessel designated "SD Lucifer" - a capital ship of immense proportions. Several additional missions follow and set up the games climax in a subspace battle to take down the Lucifer.
The story progression in Descent: FreeSpace was furthered through mission briefings and in-mission conversation between pilots and gameplay designed was inspired by its space-sim predecessors X-Wing , TIE-Fighter, and Wing Commander. Gameplay allowed for custom loadouts of weapons configurations and adjustment of the ship priorities between speed, shield strength and weapon energy. Weapons options ranged from pulse lasers to multi-warhead swarm missiles and targeting computers aided in the targeting of moving objects and ships.
Descent: FreeSpace received the expansion pack ' Silent Threat' before getting its true sequel FreeSpace 2 in December of 1999.
Though the games bare the name 'Descent' which invokes thoughts of the Descent series, the FreeSpace games are unrelated to the universe the Descent games are set in. However Parallax Software, the developers of Descent were split into two studios after the release of Descent 2. The first was Outrage which shut down in 2003. The second was Volition, who developed Freespace, the Descent name was only chosen to avoid trademark issues with another companies disk compression utility also known as FreeSpace. The game is now more commonly known as Conflict: Freespace - The Great war or simply Freespace - The Great War.
A modification is available for the games sequel, Freespace 2, that ports the campaign from Freespace to the Source Code Project. This offers better sound quality in cut scenes and briefings and more modern graphics.