Continuity mistake: Widescreen version: When Luke and Vader are fighting in the carbon-freezing chamber, as Vader says, "Only your hatred can destroy me.", the hose hanging from the ceiling behind Luke is pointed straight down, but in the previous shot, it was bent. This has nothing to do with camera angles - watch the smoke coming from it, it changes direction as well. (01:40:40)
Continuity mistake: When Vader addresses the bounty hunters, Piett says, "Bounty hunters-We don't need their scum.", and starts walking towards a corner. In the next shot, he is already at that corner. (01:03:20)
Continuity mistake: During the battle of Hoth, the weather keeps changing between shots. The sky alternates between being totally clear of clouds, clear with some clouds, and very grey and overcast.
Continuity mistake: When Vader attempts to turn Luke to the dark side, he says, "With our combined strength, we can end this destructive conflict and bring order to the galaxy." As the second shot begins, Luke is standing much closer to the structure he's holding onto, than in the previous shot. (01:46:20)
Continuity mistake: During the battle of Hoth, Wedge flies a full circle around the AT-AT walker and when the walker begins to fall, you can see the cable around its legs, but in a side view of the walker falling, the cable is nowhere to be seen.
Continuity mistake: When Han says "Watch this!" when trying to get the Millennium Falcon to jump into hyperspace, C3PO turns his head around twice. (00:37:40)
Continuity mistake: When Han attempts to shoot Vader, Vader deflects the bolts into the walls. As he says, "We would be honored if you would join us," you can see burn marks by the door and on the wall to the left. Two shots later, the burn mark by the door has changed shape and size, and in the last shot of the scene, the other one has disappeared. (01:25:05)
Continuity mistake: When Han punches Lando, Lando's cape stays on his back, but in the following shots, it's folded over his arm., before he puts it back on again. (01:29:45)
Continuity mistake: When Lando invites Han, Leia and Chewbacca for refreshments at Cloud City, we see a box containing C-3PO's remains and the head of C-3PO is looking to the right. But when the four of them leave the room, we see a close up of C-3PO's head and it is now looking to the left. (01:27:30)
Continuity mistake: At the rebel base, Leia is informed that there is nothing more can do about Han and Luke until the morning and agrees to the hangar doors being closed. In the wide shot, you can see the doors starting to close, although the code hasn't been put in yet. In the next shot the code is put in and the doors start closing again. (00:12:10)