Revealing mistake: When the Millennium Falcon is being pursued by the Star Destroyers after leaving Hoth, for a few seconds you can see the light of the ship through one of the Star Destroyers as the Falcon flies in front of it in the second shot. (00:35:25)
Continuity mistake: Just before Leia gives the order to evacuate and leaves the control room on Hoth, C3PO can be seen in the background with his hands over his head. The shot changes to a closeup of him, and his hands are now down at his waist.
Continuity mistake: When Yoda and R2-D2 are engaged in a tug-of-war over the little flashlight, Yoda hits him several times with his walking stick. When Artoo lets go, the stick is pointing upwards as Yoda hits him one last time, but in the next shot, Yoda is using it as a walking stick again and it is pointing downwards.
Revealing mistake: Look carefully at the end of the cavern where the Millenium Falcon enters the giant asteroid. It's a dark blue circle, because the light is dim. But there is a little white circle on the right and the two circles are much brighter on the left side. It's because it's an image of a planet with a moon.
Audio problem: When Han punches Lando, his hand never makes any contact with Lando's face, and the sound effect is heard after his hand goes past it. (01:29:20)
Revealing mistake: When we see the Star Destroyer for the first time, there are three of them on screen. The one on the top left, can still be seen even after another Star Destroyer came into frame and blocks the view.
Continuity mistake: Widescreen version: After Vader chokes Captain Needa, he talks to Admiral Piett. The distance between Piett and the officer next to him differs between shots, depending on the camera angle. (01:10:55)
Continuity mistake: After R2-D2 opens the door to the landing platform during the escape from Cloud City, the droid exits through the door. Some shots later, he is back inside. (01:43:55)