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: During the lightsaber duel, Vader throws his at Luke. The catwalk behind Luke explodes, but if you watch in slow-motion there are two explosions: one some inches over where the lightsaber actually hits and one far on the left.
Revealing mistake: In the scene where Han and Chewie sneak up on the two storm troopers on the Endor moon, Han steps on a twig, it snaps, and the trooper turns around and punches him. Watch in slow motion as the punch is released, Han starts falling backwards before the fist hits him.
Stupidity: When trapped in the net, Luke asks Han if he can reach his lightsaber. Han says that he can, but turns out he can't. Luke has the force. Why doesn't he just use it to make the lightsaber fly into his hand instead of having Han reach for it in vain?
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.