Star Trek: Deep Space Nine -- The Fallen is a single-player action game seen simultaneously from the perspective of three different crewmembers: Captain Benjamin Sisko, Lt. Commander Worf, and Major Kira Nerys, all of Starfleet Command. Each protagonist has an individual style of investigating or fighting, and enemies are dispersed with a variety of phasers, disrupters, or melee weapons. In addition to combat, the adventure focuses on exploration and puzzle-solving.
Upon discovery of an ancient cult that worshipped gods known as Pah-wraiths in some long-abandoned ruins, Obanek Keelan began a quest to locate three mystical orbs rumored to release the gods' power. To his dismay, the the Bajoran government declared his discovery blasphemy and closed the ruins. Angry, yet determined, Obanek made the discovery of the orbs his life quest. Another group, the Cardassians, also want to use the orbs' power to help them harness great weapons for their own war with the Dominion.
Actors from the television show reprise their roles by lending voiceovers. Quests have different outlooks, though many missions are interlaced. Both melee and projectile weapons are available, and missions occur on several planets as well as aboard Deep Space Nine.
Though action is mouse-driven, hot keys are available for easier access to weapons. A "Personal Access Display Device" is used to access options, allowing players to save the game and view mission objectives. A tricorder helps locate enemies and allows strategic planning. Other featured weapons include a type 3A Phaser Rifle, "gravatic" mines, grenade launchers, pulse rifles, shock blades, plasma throwers, and an EM pulse cannon. A respirator is available for underwater exploration, and medical kits with hypo sprays keep characters healthy.