Other mistake: Widescreen version: When Luke and Vader enter the Emperor's throne room, the stars seen through the window behind the Emperor move a little faster than the stars seen through the two other windows. (01:26:35)
Audio problem: After landing on Endor, Han says, "This whole party will be for nothing if they see us.", but his lips hardly move. (00:55:10)
Continuity mistake: At the end of the scene when the Emperor and Darth Vader walks through the Death Star's hangar, you can see that the Emperor walks past a squad of grey suited commanders. But in the next shot there are only white dressed storm troopers and scout troopers on the right side of the Emperor. And if you compare the last shot in the scene with the earlier shots you can see differences in the soldiers' placements. (00:37:45)
Continuity mistake: When Luke pulls Vader away from the edge of the abyss, a wall can be seen behind them, quite close to them. But several times earlier in the movie, there was no such wall in this area of the Emperor's throne room. (01:52:40)
Revealing mistake: Right before Luke leaps from the speeder bike to the scout trooper's speeder, there's a shot showing the front of the speeders. Notice the area surrounding the speeders in this shot. During the rest of the speeder bike chase, the speeders pass through this area several times, even though they are not flying in circles. This can be seen, for example, from the sunlight hitting the ground and the tree on the left side with a bush in front of it. Also, one of the shots where this area is seen is the shot before the speeders pass two more scout troopers, but the background has been flipped.
Continuity mistake: After the Death Star explodes, in the first shot of the Ewoks, a grey one is standing next to Chewbacca (who can be seen on the extreme right). In the next shot, this Ewok has disappeared, and another one is standing next to C-3PO. This Ewok has disappeared in the following shot, and a third one, who was nowhere to be seen in the previous shot, is now standing in front of Chewbacca. Also, C-3PO, Chewbacca and the Rebel next to him are standing in different positions between shots. (00:58:15)
Continuity mistake: During Luke and Vader's conversation on Endor, as Vader says, "That name no longer has any meaning for me," he is pointing the hilt of Luke's lightsaber at Luke's chest. In the next shot facing Luke, the hilt is nowhere to be seen, even though it should be, because of its position in the previous shot. (01:20:35)
Continuity mistake: When Jabba pulls Leia's chain in the sail barge, Bib Fortuna is standing on the right side of the screen, a few meters away. He then takes one step forward, but in the next shot he is suddenly standing behind Leia, as he's pushing her against Jabba. He was too far away from them in the previous shot to have reached them that quickly.
Continuity mistake: When they get ambushed in the shield generator complex, an imperial in black appears from the right of the screen in front of the ledge with the railing. Han throws the container in his hands at the imperial. If you notice, the imperial actually begins to jump over the railing before the box even hits him.
Revealing mistake: When C3PO and R2D2 are picked up in the sand, there is no sand falling off them. Obviously, C3PO's legs and R2D2 where just placed behind some sand (and not in it) or they used blue screen in this shot.
Continuity mistake: When Luke and Han are being executed on Tatooine, Han says his eyes are getting better but still bad. Then he looks directly at Luke and says "You're gonna die here." In the very next line of dialog, Han's head is turned a different way. It looks like it was a different shot.
Continuity mistake: When Vader's shuttle is approaching the Death Star, the crew in the control room of the Death Star are wearing black gloves. One of them then reaches forward to press a button, but in the close-up of his hand pressing the button, the hand is not wearing gloves at all. This can only be seen in the widescreen version. (00:02:25)
Continuity mistake: In the scene of the rebels planting explosives in the bunker, the first shot shows someone with gloves planting an explosive. Then it cuts to a wide shot of Han's team and none of them are wearing that style of glove. (01:51:10)
Audio problem: When Lando is inside the Death Star we see a shot of him scraping the side of some metal. Then he says "That was too close." His voice has the same echo applied to it as the sound effects in the narrow metal tunnel. For unknown reasons this mistake wasn't even fixed in the DVD.
Other mistake: During the final confrontation with Vader on the Death Star, Luke bashes a catwalk railing with his light saber several times, but there are no burns, marks, or indentations on it at all. Considering the power of a light saber (Qui Gon melted a steel door in Phantom Menace), some damage should be visible. Only when he hacks off Vader's hand does the light saber slice through the rail.
Continuity mistake: When the Emperor is torturing Luke, in the shot after Luke groans, "Father, please", Vader and the Emperor are standing further away from each other than in the previous and following shots where both are visible. (01:51:20)
Other mistake: When the ground battle on Endor begins, Leia runs to the bunker, and as the doors close, she fires a shot. In the original version of the movie, the blaster smokes, but no laser beam comes out of it and no sound is heard (do not confuse this with the sound of the doors closing). In the Special Edition, the sound has been added, but the laser is still missing. (01:38:05)