Other mistake: In the original version, in the first wideshot of the Super Star Destroyer, on the right side of the screen, the light of a Star Destroyer (but nothing else of it) can be seen just flying through space for two seconds before it disappears. This mistake is fixed in the Special Edition.
Continuity mistake: After Leia, Han and Chewbacca walk down the stairs in the carbon-freezing chamber, as the shot ends, Han is turning towards a stormtrooper behind him. In the next shot, he is turned in a different direction, and Leia's head is facing another way. The position and existence of some of the people around them changes between the two shots as well. (01:31:10)
Continuity mistake: When Han and Leia kiss in the Millennium Falcon, Leia's arms are around Han's head in the wideshot, but not in the close-up. (00:49:55)