Continuity mistake: After Darth Vader kills Obi-Van Kenobi, Luke shouts "No!" and then there is a gunfight with stormtroopers. During this, R2-D2 is seen going up the ramp into the Millennium Falcon. But a few shots later, when Han Solo says "Come on!", you can see R2-D2 at the bottom of the ramp and he going back into the Falcon for a second time.
Visible crew/equipment: When Luke and Leia are stuck on the bridge, just before the stormtroopers arrive on the opposite platform Luke remembers the cable and sees the thruster like things over the top of him and Leia, when we get a view of them a small shadow bobs up and down at the centre bottom of the screen.
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.
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.
Continuity mistake: Special Edition: When Han is talking to Jabba the Hutt, when Jabba begins to says, "What if everyone who smuggled for me dropped their cargo at the first sign of an Imperial starship?", Chewbacca can be seen walking behind them. In the next shot, he is suddenly walking next to a wall that was nowhere near him in the previous shot. In the following shot, he is back to his original position.
Continuity mistake: When a confrontional alien thug threatens Luke and Ben interferes, the thug has his hand on Luke's upper arm. In the next shot, his hand is on Luke's shoulder.
Deliberate mistake: As noted in another mistake, Red Leader's helmet microphone changes sides before he crashes. Because some shots during the attack on the Death Star are flipped, this also happens to Rebel pilots earlier in the battle: Red Leader when he says, "All wings, report in", Wedge after a shot of Leia and C-3PO monitoring the battle, Luke when Red Leader says, "There's a lot of fire coming from the right side of that deflection tower" and when Luke says, "I'm hit, but not bad" and finally Red Leader after Gold Leader is killed.
Revealing mistake: When the droids head towards Tatooine in their escape pod, a rotating imperial ship is shown in the pod's window, getting smaller as the pod moves away. Regrettably, the star field gets smaller at the same rate as the ship, something that would only happen if you were moving away from a photograph, painting etc.
Continuity mistake: After Owen buys C-3PO from the Jawas, Luke says, "All Right. Come on." and R2-D2 begins to turn his head/dome. In the next shot, his head is still turning, but his dome is in a different position from the previous shot, evident from the droid's features.
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.
Continuity mistake: As R2-D2 is rolling through the canyon, he's on a smooth part of the land. He then stops and looks around. When he starts moving again, the terrain has changed and is now full of rocks and pebbles.
Deliberate mistake: Just after Obi Wan kills the two aliens in the Cantina, there are two quick "reaction shots" from both ends of the bar. If you are quick, you can see that they are both shots of the same end of the bar with one shot flipped. You can see the same human with the light blue/dark blue suit on in both shots.
Continuity mistake: In the scene where Luke finds the remains of his aunt and uncle, in the shots from behind Luke, the wind is blowing from his left. In the shots facing him, the wind is blowing from his right.