A full copy of the voice script fills up ten 5-inch binders.

Before you open the door to the final battle against Darth Malak on the Star Forge, connect more than one controller, pull both triggers and press the Y button on each controller at the same time. This will show a secret scene where Malak turns into a Twilek and starts dancing with you.

The world Sleheyron, a planet in Hutt space and one of the most industrialized worlds in the galaxy paved over with layer upon layer of gas refineries, landing bays, slave pens and ship construction yards, was originally going to be a visitable world in the game. The biggest level of the planet was going to be a massive coliseum where the Hutt lords pitted their gladiator slaves against one another. The world was left out due to time constraints.

Several sections of Tatooine were cut out due to time constraints. The Star Map was originally to be located in a Sarlacc pit instead of a Krayt Dragon's lair. Players would have to find the sarlacc in a cave complex and then enter it without getting eaten. Later the player could become a messiah of the Sandpeople and lead them to stand up against Czerka.

The character Juhani is a lesbian. However, due to an error in the initial release of the game she could be romanced when playing as a male character. This was fixed in later editions, and patched out of the PC version.

One of Canderous Ordo's stories he tells the player is about his encounter with a strange meteorite-like object in the Crispin system. He describes the object as about a dozen meters in length, having a rocky growth pitted by scores of micrometeorite scars, and featuring thermal projectiles. The ship then fled outside of the known galaxy and into the unknown void.

The object which Canderous describes seems to be a Yuuzhan Vong ship, possibly a Yorik-et, aka a Coralskipper. The Yuuzhan Vong was a mysterious alien species which came from outside the known galaxy in Star Wars lore. They would later play a major threat in Star Wars lore, 25 years after the events of Star Wars Episode IV: A New Hope in the original "Legends" continuity, approximately 3,000 years after the events of Star Wars: Knights of the Old Republic.

Several images on the Steam Store page and on the back of the Xbox version show scenes that are impossible in normal gameplay.

-The Steam Store page shows Bastila, the player character, and Carth fighting Mandalorians on the Unknown World.
Spoiler:It is impossible to have both Carth and Bastila in the party at this time. The only way to get Bastila in the party is to go inside the temple (which can only be entered with Jolee Bindo and Juahni), and choose the dark side option, leaving with Bastila alone. Carth cannot be added to the party at this time.

-The Steam Store page, and a different image on the back of the Xbox version, both show HK-47 on Taris.
Spoiler:HK-47 joins the party on Tatooine, which can only be reached after the destruction of Taris.

There's a reference to the first Star Wars movie, "Star Wars Episode IV: A New Hope."

When Admiral Karath is interrogating the player, Bastila, and Carth, he asks for the location of the hidden Jedi Academy on Dantooine. One dialogue option has the player saying, "Alderaan. It's on Alderaan."

In the movie, Grand Moff Tarkin interrogates Princess Leia asking for the location of the secret Rebel base to which she replies with, "Dantooine. They're on Dantooine." Tarkin knows this is a lie and then proceeds to use the Death Star to destroy Leia's home planet of Alderaan. In the game, Darth Malak, the game's main antagonist, bombards Dantooine, resulting in the destruction of the Jedi Academy.

In the final game, it's impossible to take Bastila onto Korriban, as she fears she will be recognized by the Sith running the planet. However, she and other characters have voice clips related to her being on Korriban.

If one mods the game to allow Bastila on Korriban, it is possible to hear the the fully implemented voice clips, suggesting that her removal from Korriban was done late into development.

In the Xbox version of the game, by connecting a first-generation controller (A.K.A. "The Duke" controller) into the fourth port on an original Xbox console, the pitch and speed of all dialogue in the game can be shifted higher and faster using the White action button, and lower and slower using the Black action button.