Revealing mistake: When an Imperial Officer is running down the tunnel in the Detention Block towards Han, Luke and Chewbacca, Han clearly shoots the top-left hand corner of the tunnel and the Imperial Officer falls down the stairs as if he shot him. (01:14:55)
Suggested correction: This is definitely intentional, not an error. We see stormtroopers being killed by nearby shots throughout the movie, blasters having a smaller 'shock wave' is just a retcon.
Continuity mistake: When Leia shoots a hole in the detention area wall for their escape, the hole is not big enough to jump through, but when they all jump in, the hole is much bigger. (01:15:10)
Continuity mistake: In the Detention Block, Han and Luke are in their stormtrooper outfits and are firing at the enemy. They go to a shot of Han then to Luke. Luke's white shoulder pads of his stormtrooper outfit are clearly missing, and you can see a black undergarment. They then go back to Han and then back to Luke again, where the shoulder pads are now back. (01:15:20)
Continuity mistake: In two shots of Chewbacca in the beginning of the trash compactor sequence, there's a little area of blue paint on the right side of the hatch. For the rest, the blue spot is missing. (01:16:00)
Continuity mistake: Widescreen version: In the trash compactor, as Han says: "What an incredible smell you've discovered." Leia is leaning against some garbage, and then turns her head. In the next shot, she is no longer leaning against the garbage, and her head is turned another way. (01:16:05)
Continuity mistake: When Han is about to fire his blaster at the door of the garbage compactor, Chewie moves away from the door. In the next shot, he is back in his previous position, and moves away from the door again. (01:16:10)
Continuity mistake: Right before Luke yells at Han after he fires his blaster in the trash compactor, there's a wideshot where Han is sitting among some garbage and holding his blaster with one hand. In the next shot, he has turned the other way and is standing, holding the blaster with two hands. (01:16:15)
Continuity mistake: In the trash compactor, after the dianoga roars, there's a close-up of Leia standing straight up, with her arm over the large iron pole. In the next shot, she is crouching, and her arm is underneath the pole. (01:16:40)
Continuity mistake: When the dianoga grabs hold of Luke in the trash compactor, his legs are together. In the next shot, they are much further apart. (01:17:05)
Continuity mistake: In the trash compactor, as Han says, "I've got a bad feeling about this", Leia's arm is held straight, but in the next shot, it is bent. (01:18:15)
Revealing mistake: When they are diving into the trash compactor on the Death Star, one can see the metal bars of the grid, that had previously been cut through, wobble like rubber when one of the team brushes against them. (01:18:20)
Continuity mistake: When Han and Leia try to use a pole to stop the trash compactor, Leia says, "Help me." Two shots later, Han can be seen lifting the pole. In the next shot, Leia is suddenly lifting it with him, and Han is holding the pole differently. (01:18:40)
Continuity mistake: Widescreen version: In the trash compactor, before the scene where the droids leave the control room, both ends of the pole used to stop the compactor are coming into contact with the walls. After the droids leave the room, the right end of the pole is not coming into contact with the wall. (01:18:50 - 01:19:45)
Other mistake: When the stormtroopers break into the control room, the stormtrooper on the right of the screen hits his head on the door frame. On the DVD release they've added a thump when he hits it. (01:18:55)
Revealing mistake: In the shot where Han Solo and Luke jump down the garbage chute, Smoke outlines the end of the corridor, revealing it is a board with the scenery on it. (01:19:00)
Continuity mistake: After the droids leave the control room of the Death Star, there's a close-up of Luke in the trash compactor, pushing against some garbage. In the next shot, he is pushing against the wall. (01:19:45)
Continuity mistake: In the trash compactor, Han says, "One thing's for sure, we're all going to be a lot thinner." In the next shot, Han and Leia are both standing in a totally different position. For example, both of them are looking in another direction, and Han's left hand is in a different position. (01:20:15)
Continuity mistake: Widescreen version: In the trash compactor, Han says to Leia, "Get on top of it." In the next shot, Leia can be seen in the background, in a totally different position from the previous shot. For example, she is holding the pole differently. (01:20:25)
Continuity mistake: After Luke gets pulled underwater in the trash compactor, he is shown with a piece of garbage on his forehead in one shot. In the next shot his forehead is clean, but in the following shot, the piece of garbage is back again. (01:21:35)
Continuity mistake: There's only grayish objects in the garbage compactor but while Luke and Han are removing their uniform, many orange objects appears in it. (01:22:10)
