Bug: In Hollow Bastion, right after you defeat the Maleficent Dragon and before you fight Riku/Ansem, during the movie scene where Sora sees Kairi on the ground in front of the keyhole in the hall containing the Princesses of Heart, Sora lifts Kairi and shakes her up and down to wake her up. The pendant on Kairi's necklace stays suspended in the air when he shakes her until the shot changes.
Continuity mistake: Before the fight with the pot barrel spider/centipede boss in Agrabah, after Iago steals the lamp from Aladdin he lands on Jafar's left shoulder. After Jafar says, "Attack," there is a cut and Iago is no longer there.
Continuity mistake: When Riku throws the board down on the beach, for the raft, it vanishes in the next shot.
Other mistake: When Sora and the gang return to confront Cerebus in the Colosseum (when Hercules rescues Cloud), you can see Sora's keyblade pass through Goofy's shield.
Continuity mistake: In the scene when Sora confronts Ansem on Destiny Island, when Riku changes into him, there is a height difference. When they change, Ansem is as tall as Riku yet he is at least twice Riku's height then in the next shot he's taller again.
Continuity mistake: In some cut-scenes, Sora's Keyblade changes back to the original Kingdom Key he starts out with, even when the player is using a different one.