Deliberate mistake: After the Tusken Raider has attacked Luke, he raises his stick over his head and shouts. The movement of his clothing is extremely unnatural. During the editing, they put the same footage forward, then backward many times, to add emphasis to his movements, but it looks decidedly odd. (00:29:02)
Deliberate mistake: As the Lotus drives off the pier and enters the water, the exposed underbody is that of a normal car. After it enters the sea, the underbody we see is completely sealed, which it needs to be to allow the car to submerge.