Continuity mistake: After the crash landing on Coruscant, Anakin, Kenobi, and Palpatine take a shuttle to the Jedi Council. In the first shot as the shuttle is landing, all shadows are parallel with the edge of the landing area. In the next shot when the shuttle doors open, all shadows have shifted 45-degrees clockwise.
Continuity mistake: In the first shot of the scene where Yoda leaves Kashyyyk, as Tarfull begins to walk towards Chewbacca, Yoda is several metres away from them. In the next shot, he is much closer to them, and Tarfull, who is still walking, is further away from Chewbacca than in the previous shot. (01:22:20)
Continuity mistake: As Anakin is reentering the elevator from the top, you can see the hole being very close to the entrance door of the elevator. As we see from the subsequent shot, Anakin is landing between Obi-Wan and the aft elevator wall (Obi-Wan does a half turn to face Anakin), whereas according to the hole, Anakin should have landed either directly on top of Obi-Wan or between Obi-Wan and the elevator door. (00:10:30)
Continuity mistake: When Obi-Wan gets on the intercom with R2 the first time on Grievous' ship, as it cuts to R2 backing up against the corner hiding from the droids we can see that there is no light casting his shadow. When it cuts to R2 again two shots later, bright light suddenly appears, casting his shadow. (00:09:10)
Continuity mistake: When Anakin, Obi-Wan and Palpatine are falling down the elevator shaft and use the hook grip to swing themselves in the elevator door, the land on the light on the floor from the ceiling. When it cuts to them getting up they have moved two feet away from the light. (00:16:45)
Continuity mistake: When Bail Organa is standing on the landing platform of the Jedi Temple, a clone trooper says, "I'm sorry sir. It's time for you to leave." and points his blaster at him. In the next shot, he is holding it much lower than in the previous shot. (01:21:15)
Continuity mistake: In the first shot of the scene where Luke and Leia are born, Padmé's head reaches the top of the black area of the bed. Her head is seen in all the following shots, and her position doesn't change. But when she says, "Oh, Luke", her head has moved about 10 cm down from her previous position. (02:00:30)