Star Wars: Knights of the Old Republic (KotOR) is a role-playing video game developed by BioWare and published by LucasArts. It was released for the Xbox on July 15, 2003, for Microsoft Windows on November 19, 2003, and on September 7, 2004 for Mac OS X. The Xbox version is playable on Xbox 360 with its Backward Compatibility feature. The PC version was re-released as part of the Star Wars: The Best of PC collection in 2006 as a limited release. The sequel, Star Wars: Knights of the Old Republic II: The Sith Lords, was developed by Obsidian Entertainment at BioWare's suggestion as BioWare wanted to focus on their own intellectual properties. The soundtrack for the game was written by Jeremy Soule.
This game's system is based on Wizards of the Coast's Star Wars Roleplaying Game, which is based on the d20 role-playing game system derived from the Third Edition Dungeons & Dragons (DnD) rules. 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 unlocked every few level-ups, while the player is given skill points to distribute among his or her 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 at 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 DnD rules. While these are not displayed directly on the screen, the full breakdown for each action (including die rolls and modifiers) are accessible from a menu.
For much of the game, the player can have up to two companions in his or her 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 dialog, 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 RPG gameplay, there are several minigame events that come up over the course of the game. The player can engage in swoop racing to gain 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 playing card game known as pazaak, which is similar to the game of blackjack, to gamble their money.