Visible crew/equipment: During Luke's conversation with Ben's ghost, you can see a boom microphone in the background. This applies to the original wide-screen version.
Revealing mistake: In many of the scenes taking place in outer space, if you look closely you can see polygon borders surrounding space vehicles (X-Wings, Star Destroyers, and even the Death Star) indicating the objects being superimposed into the outer space background. [This mistake may only apply to the Blu Ray version.]
Continuity mistake: As C-3PO and R2-D2 enter Jabba's throne room, C-3PO is walking down a small set of stairs with R2-D2 not following after him. When C-3PO again can be seen after the pillar blocking the camera's view, R2-D2 shows up behind him shortly after. (00:07:55)
Continuity mistake: Outside the bunker the position of the bodies keep changing or moving throughout the battle on Endor.
Continuity mistake: When R2-D2 is shot by an Imperial stormtrooper whilst trying to open the shield generator's doors, he goes into the side wall and you can see a door open on his body with an interface arm sticking out of it. But when Han shoots the stormtrooper dead, we cut back to R2, and the door that was originally open is now closed.
Continuity mistake: When the Rebel fleet is preparing to make the jump to hyperspace to the second Death Star, the small fighters move first. Then the big ships. But when the big ships move into hyperspace, there are only the Medical Frigate, some transports and some Blockade Runners. What happened with the big Correllian command ships?
Revealing mistake: Look carefully at the close-ups of C3PO's waste where the exposed wires are. You can tell it's fake wiring on top of a black suit which is particularly noticeable when the actor inside the costume as his stomach is moving when he has to breathe.
Factual error: The cockpit for the Falcon is on the right side of the ship. Why, from the inside, does it always look like it's directly in the center of the front of the ship? The visuals outside are not offset like they should be for a cockpit that's not in the middle of the ship.
Suggested correction: They're not offset - you can't see the rest of the ship to the left because of where the cockpit windows are. We're just looking forwards into space.
Continuity mistake: During the speeder chase scene, Leia jumps from her speeder and it blows up, the stormtrooper then hits a tree. The camera shows the tree as a hollow shaft, but when the stormtrooper smashes into it, suddenly it is solid. (01:58:15)
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)