Players choose from three basic character classes at the beginning of the game and later choose from three Jedi subclasses. Beyond class, a character has "skills" stats, tiered "feats," and later on, tiered Force powers, similar to magic spells in fantasy games. Feats and Force powers are generally unlocked upon level-up, while the player is given skill points to distribute among their skills every level.
Combat is round-based; time is divided into discrete rounds, and combatants attack and react simultaneously, although these actions are presented sequentially on-screen. The number of actions a combatant may perform each round is limited. While each round's duration is a fixed short interval of real time, the player can configure the combat system to pause at specific events or the end of each round, or set the combat system to never automatically pause, giving the illusion of real-time combat. Combat actions are calculated using Dungeons & Dragons rules, particularly the d20 System. While these are not displayed directly on the screen, the full breakdown for each action (including die rolls and modifiers) is accessible from a menu.
For much of the game, the player can have up to two companions in their party. These companions will participate in combat. They can be manually controlled by the player, or act autonomously if the player does not give them any input. Outside of combat, the companions will randomly engage the player or each other in dialogue, sometimes unlocking additional quests. They will also participate in conversations the player has with other non-player characters.
Non-combat interaction with other characters in the game world is based upon a dialogue menu system. Following each statement, the player can select from a list of menu responses. The dialogue varies based on the gender and skills of the main character.
The alignment system tracks actions and speech—from simple word choices to major plot decisions—to determine whether the player's character aligns with the light or dark side of the Force. Generosity and altruism lead to the light side, while selfish or violent actions will lead the player's character to the dark side, which will alter the character's appearance, turning their eyes yellow and their skin pale.
In addition to the standard role-playing gameplay, there are several minigame events that come up over the course of the game. The player can participate in swoop racing to earn money, and sometimes interplanetary travel will be interrupted by enemy starfighters, which begins a minigame where the player controls a turret to shoot down the opposing starcraft. The player can also engage in a card game known as pazaak, which is similar to the game of blackjack, to gamble money.
Plot
The story takes place approximately 4,000 years before the rise of the Galactic Empire. Darth Malak, a former Jedi, Dark Lord of the Sith, and Darth Revan's former apprentice, has unleashed a Sith armada against the Republic. Malak's aggression has left the Jedi scattered and vulnerable; many Jedi Knights have fallen in battle, and others have sworn allegiance to Malak.
The game opens with the player's character—the player can choose a face and be male or female (canonically a male)—awakening aboard a Republic ship, the Endar Spire, which is under attack by Malak's forces over the city world of Taris. Republic soldier Trask Ulgo soon arrives and informs the player character that they are under attack. Fighting their way to the escape pods, Trask and the player character are soon confronted by Sith Lord Darth Bandon. With no other options, Trask sacrifices himself while the player continues to make their way to the escape pods. The player character soon meets up with Carth Onasi, a skilled pilot and Republic war hero, and they escape the doomed warship.
Crashing on the surface of Taris, the player character is knocked unconscious, and Carth pulls them away from the wreckage. After suffering a strange vision, the player character awakens in an abandoned apartment with Carth, who explains that Taris is currently under martial law by Malak's forces who are currently searching for the Jedi Knight Bastila Shan, known for her mastery of battle meditation, a Force technique which strengthens one's allies and weakens one's enemies during battle. Carth and the player character go in search of her and manage to meet new companions along the way, such as the Twi'lek street urchin Mission Vao and her Wookiee companion Zaalbar. The group eventually finds and rescues Bastila from the Black Vulkar gang. With the help of utility droid T3-M4 and Mandalorian mercenary Canderous Ordo, the group escapes Taris aboard the star freighter Ebon Hawk, moments before Malak's fleet decimates the planet's surface in a vain effort to kill Bastila.
While taking refuge at the Jedi Academy on Dantooine, the player's character trains to be a Jedi, discovers a "Star Map," and learns of the "Star Forge," the probable source of Malak's military resources. The player's character and their companions search planets across the galaxy—Dantooine, Manaan, Tatooine, Kashyyyk, and Korriban—for more information about the Star Forge, gaining new companions along the way such as the Cathar Jedi Juhani, assassin droid HK-47, and 'Grey' Jedi Jolee Bindo. Through the course of their travels, the player will eventually discover their character's true identity—the brainwashed Darth Revan, whom the Jedi Council on Dantooine took in and subjected to memory modification so that he would no longer be a threat to the galaxy, the various visions they had been experiencing being Revan's memories. Darth Revan had been injured when attacking a Republic planet because Darth Malak turned his ship's guns on his former master, intent on usurping him. Because Bastila was aboard Revan's ship with a Jedi strike force, she was able to heal him and bring him to the Jedi Council on Dantooine. Her actions lead to the force bond between her and Revan, which plays a role later in the game.
