Continuity mistake: When a blast rocks the command centre during the battle on Hoth, C-3PO is thrown backwards into Han's arms. As the wideshot leaves, Threepio is leaning backwards, supported by Han, but in the next shot, both of them standing upright in a normal way. Toryn Farr, the woman sitting behind them, has changed position as well. (00:30:40)
Continuity mistake: When Chewbacca is choking Lando, as Leia says, "We don't need any of your help.", Lando is standing on his knees. In the next shot, only his head can be seen, but the position of his head and Chewie's arms shows that he is now standing straight up. In the next shot, he is on his knees again. (01:38:15)
Continuity mistake: After the carbonite block is pulled out of the carbonite freezer, there's a close-up of Leia leaning towards Chewbacca. In the next shot, she is not leaning on him, and then Chewie pulls her towards him again. (01:33:05)
Audio problem: In the carbon freezing chamber, Han says to Chewbacca, "The Princess - you have to take care of her". When he says, "You have to take care of her", his head is shown from behind, but the motion of his jaw doesn't match the words. (01:35:35)
Continuity mistake: When Luke is attacked by the ice creature all the scars are on the right side of his face, but right before he talks to Obi-Wan you see a big scar on the left side of his face, then when he talks to Obi-Wan you can see there are no scars on the left side of his face. (00:11:00 - 00:13:05)
Continuity mistake: When Lando releases Leia and Chewbacca, as Leia says, "What do you think you're doing?" her body is turned in a different direction from the previous shot, and she's holding the blasters differently. (01:37:55)
Continuity mistake: When Janson (Wedge's gunner) fires the harpoon at a leg of an AT-AT, in the first shot of the snowspeeder flying around the AT-AT, the speeder casts a shadow on the snow. In all other shots of this sequence, there is no shadow of the snowspeeder.
Revealing mistake: Right after Luke and Darth fight for the first time, Darth gets kicked off the Carbonite freezer. Then Luke jumps down to fight him again. After he jumps, you hear what sounds suspiciously like a trampoline. Then in the lower right screen, you can see Luke's head pop back up into frame. Widescreen Version only, although the sound is audible on the fullscreen version too.
Continuity mistake: During the escape from Hoth, C-3PO is far behind Han and Leia as they are running to the Millennium Falcon after the cave-in blocks their path. When they reach the door, he is much closer to them. (00:32:40)
Revealing mistake: In the original (not Special Edition): When the AT-ATs are attacking the Hoth base, they do a camera angle from inside Luke's cockpit. As his snowspeeder is passing through the legs of an AT-AT, part of the cockpit becomes translucent and you can slightly see the AT-AT through a metal bar.