Revealing mistake: When Luke jumps from Jabba's prisoner's skiff, you can see a stick supporting the "floating" skiff he jumps over to. (00:32:15)
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)
Revealing mistake: When Luke is fighting on a skiff, he kicks one of Jabba's men in the head, causing him to fall off. Luke's foot doesn't make any contact with the person. (00:33:48)
Revealing mistake: When Luke and Leia swing to the skiff on the rope, in the shot from the back, Leia is obviously played by a stunt woman - the birthmark on Carrie Fisher's back, which can be seen a few times on board the sail barge, is missing. (00:35:00)
Revealing mistake: When Luke and Leia swing from the deck on to the skiff, you can see that the man playing Lando Calrissian is not Billy Dee Williams but his stunt double. (00:36:25)
Revealing mistake: When Jabba's sail barge begins to explode, you can see that one of the floating skiffs is standing on stilts. (00:36:30)
Revealing mistake: In the scene where Han and Lando are talking in the hangar after the big meeting about the new Death Star, right when the scene opens and the shot pans down, notice how half the hangar is real and the other half is a matte painting. (00:49:30)
Revealing mistake: The interior matte painting of the hangar on the Rebel ship holding the stolen Imperial shuttle doesn't match the appearance of the hangar from the exterior shot of the Rebel ship. The interior hangar shows an extended platform and four banks of vertical lights bordering the opening and then walls. From the exterior, the hangar appears to have a big light bank near the opening, and then thinner light banks behind it spaced further apart than the interior shot. The exterior shot also doesn't have a platform. (00:50:45 - 00:53:20)
Revealing mistake: If you watch closely (or play it in slow motion) when the scout trooper punches Han, you can see that the troopers hand never actually comes into contact with is face. (00:55:45)
Revealing mistake: The close-up of R2-D2 waiting for Leia to return has a clear shot of the middle wire section of C-3PO in which you can see Anthony Daniels breathing as the spandex underneath the wires expands. This is especially clear on the Blu-ray. (01:02:00)
Revealing mistake: After the heroes get snared and surrounded by Ewoks on Endor, the Ewoks mistake C3PO for a god and start bowing. There is one Ewok which only has holes where the eyes and mouth are and you can see the eyes and mouth of the person inside the Ewok costume. (01:07:50)
Revealing mistake: When Darth Vader lands on the forest moon of Endor, he exits the shuttle and his head passes through it. (01:19:30)
Revealing mistake: When Darth Vader lands on Endor there is a shot of him walking out of the shuttle, underneath the ramp there is slight black spot which probably marked the transition from studio set to matte painting. This was eliminated for the 4K release in 2019. (01:22:47)
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: After the Rebels break into the bunker, a Rebel in the background punches an officer. But if you watch closely or play it in slow motion, the Rebel's hand never comes into contact with the officer's face. (01:33:25)
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: 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: Just before Luke chops off Darth Vader's hand in the battle at the end of the movie, you can see that the bar has already been cut (the line is visible) to give the illusion that Luke cut through the steel bar with his lightsaber as well as Vader's hand. (01:48:45)
Revealing mistake: Widescreen version only: After Luke cuts off Vader's hand, the Emperor says, "Now, fulfill your destiny, and take your father's place at my side." In the next shot, Luke's lightsaber blade goes through the railing, without damaging it. (01:49:15)
Revealing mistake: When Han is running from the explosion of the shield generator on Endor, you can see his reflection in the plexiglass that is used to protect the camera from the explosion. Since the reflection isn't of Han's back, the plexiglass must be in front of him. (01:49:55)
