Continuity mistake: Just after the creature lets Luke go, Leia says, "It could be worse." In the next shot (after the compactor makes its first sound), Luke can clearly be seen saying, "What's that?", but his question has been edited out.
Continuity mistake: When Luke and R2 are doing the trench run, a tie shoots at Luke and blows the top of R2's head off. But in the next scene R2's top is on again.
Continuity mistake: During the Death Star trench run, Wedge quits because his X-Wing is damaged. The sky behind him changes from grey to black in the same shot.
Continuity mistake: When Luke sees the holograph of Princess Leia for the first time, and says, "Who is she, she's beautiful," Mark Hamill's hair is rather tousled. In the next shot of him, it's neatly combed. Then, when he gets up and says, "Well I don't know anyone named Obi-Wan...," his hair is tousled again!
Continuity mistake: When in the Death Star, there is a shot of five stormtroopers standing next to the Millennium Falcon. Two of the stormtroopers are right next to the boarding ramp. The camera instantly changes to a higher point of view and the two stormtroopers have moved about four feet farther away from their original spots.
Continuity mistake: In the scene just before Luke goes to eat dinner, C3PO has a towel or rag in his hand in some scenes, and it is missing in others. This continues as he admonishes R2 about replaying the message.
Continuity mistake: When Luke first sees the holomessage from Leia, she is bending down to stop the recording while still saying "Help me Obi Wan Kenobi, you're my only hope." When the message is viewed for the second time, she finishes speaking, looks around, and then bends down to stop the recording.
Continuity mistake: After Vader says "I have you now", in the first frame of the next shot, the TIE fighter disappears for the first frame and reappears in the second frame before it's blasted by Han Solo. It was restored in the first frame on the DVD.
Continuity mistake: During the fight against the TIE fighters, the interior shot shows the turrets on the Falcon both point straight up and down respectfully, when in other shots the top turret for example is facing forward.
Suggested correction: There is no objective up or down on a spaceship. The artificial gravity for the turrets are at 90 degree angle to the rest of the ship.
You missed the point of the mistake. Luke and Han are sitting so their backs are parallel to the deck of the Falcon, the guns are then perpendicular to their back, making them perpendicular to the deck of the Falcon. But in exterior shots, the guns are more parallel to the deck than they should be.
Continuity mistake: When Luke is repairing C-3PO at Ben Kenobi's dwelling, he initially has his hands on C-3PO's arm. In the next shot, Luke now has his hand on C-3PO's shoulder.
Continuity mistake: After Luke is attacked by the sand people, a shot shows that his head is laying to the side. In the next shot, its facing straight up.
Continuity mistake: Wide-screen version only: In the trash compactor, after the dianoga has pulled Luke into the water for the second time, Leia is leaning against some garbage. In the next shot, she is leaning forward, the other way.
Continuity mistake: When Obi Wan introduces the lightsaber, he says, "This is the weapon of the Jedi knight." C3PO is disconnected with his head down and in a lighted archway, with some blankets or something by his left side. A frame later, in a close-up, C3PO's head is up, the archway is 'in shadows and the blankets gone.
Continuity mistake: When Ben first gives it to him, Luke's lightsaber is blue, as it was when Anakin dropped it in Episode III. However, when Luke is training against the sphere en route to Alderaan, the lightsaber definitely has a green, not blue, tint to it.
Continuity mistake: When Ben says to Han in the Millennium Falcon, "In my experience there's no such thing as luck", you can see Han is resting his arm on the surface near the control panel, but in the next scene his arm is no longer on the surface.
Continuity mistake: When Luke Skywalker, Princess Leia, Han Solo, and Chewbacca are in the Death Star trash compactor, Luke, at one point, gets pulled under the water by an alien that lives there. As soon as they leave the trash compactor, however, Luke's hair is completely dry.
Suggested correction: Actually, Luke's hair is still wet; it's just drying.
Continuity mistake: When the movie starts, during the shooting C3PO and R2D2 come out from a corridor on the left. R2 is looking to the right. A shot later he is looking to the left.
Continuity mistake: When Leia, Chewie, Luke and Han dive into the garbage chute aboard the Death Star, Han is the last to dive in, about 4 seconds after Luke. Once he hits bottom, it takes Han 14 seconds to get to his feet, orient himself, and fire his blaster. Luke tries to warn Han, but Han fires anyway, and the blaster bolt ricochets around the garbage chute. Luke shouts, "It's magnetically sealed! I already tried that!" But Luke never had time to stand up and fire his blaster before Han arrived. Han was only 4 seconds behind Luke.
Continuity mistake: When Luke and Ben enter the cockpit of the Millennium Falcon during the meteor shower, Ben enters the cockpit twice between shots.
Continuity mistake: A few seconds before the Detention Block shootout begins, the 2 Death Star Troopers pull out DH-17s but after the fight begins and it cuts back to the Trooper on the left, he is holding an E-11.
