Continuity mistake: During the transport to the Sarlacc Pit, in some shots, Chewbacca is standing on Han's right. In other shots, he is standing behind Luke and Han.
Revealing mistake: At the beginning of the ground battle on Endor, two stormtroopers are knocked to the ground by the Ewoks. In the following shot, one of the troopers has a big crack in the left shoulder of his armour. The crack was obviously not there in the previous shot. (01:34:40)
Revealing mistake: When Luke and Vader enter the Emperor's throne room, in the shot from behind, you can see the stairs through Luke. (01:26:30)
Revealing mistake: In the battle on Endor, there is a shot of some Ewoks on a catapult and the at-st fires at them. Notice the second time they get fired at, the blast hits the catapult. Just before the shot ends, notice there is no damage to it. (01:40:10)
Revealing mistake: When Vader throws the lightsaber at Luke and the platform collapses, the point where the platform's columns connect to the ceiling have expanding circles of smoke coming from them as the columns detach from the ceiling, created by the charges used to sever the platform. (01:50:20)
Revealing mistake: During the speeder bike chase scenes, speeders bikes don't affect any vegetation, even though they're flying near the ground at incredible speed.
Continuity mistake: In the bunker, just after R2 gets shot, Han tries to hotwire the door. A second blast door closes, and you can see that it is very flat and cardboard looking. A few moments later, Leia gets shot, and as Han is tending to her, notice that the door is now massively armored and three-dimensional, completely different from the door seen earlier.
Continuity mistake: When Han enters the cockpit of the shuttle Tyderium, as the shot ends, he is about to walk past Luke. In the next shot, he has already walked past him and has begun to sit down. (00:50:25)
Revealing mistake: When Luke is being fed to the Rancor, in Jabba the Hutt's dungeon, there are black outlines around the beast's legs, from the composite's blue screen special effect. This was edited out in the special edition rerelease.
Continuity mistake: When Vader's shuttle exits the Star Destroyer in the beginning of the film, it is followed by two TIE fighters. The TIE fighters are far apart, but in the next shot, they're close together. (00:02:15)
Revealing mistake: In the wide-shot where Luke leaps from the prisoner skiff over to another skiff, you can see the stick used during the filming, which is much shorter than the regular one. The blade is not even glowing. (It is not just simply the hilt of the sabre, it's too long for that.). (00:32:15)