Continuity mistake: In the scene where Luke and Leia are about to swing across the canyon inside the Death Star, Leia shoots one last time. She hits the bulkhead behind the stormtrooper on the right and he falls forward. The trooper on the left continues firing (as seen in the screencap).
Continuity mistake: After the Stormtrooper tells Darth Vader the Death Star plans are not in the main computer, when Vader lifts the Rebel off his feet by his throat as the Rebel tells him they intercepted no transmissions, take note of the leg plates on the Stormtrooper to Vader's right. In the wideshot, the Stormtrooper's left leg armor does not have the knee protector plate (it looks as if it's at his right knee because the extra switched them), but in the next closeup the knee plate appears at his left knee, as it should be.
Add timeSuper Grover
Continuity mistake: In the scene after Carrie Fisher inputs the Death Star plans into R2-D2 the droid moves towards C3-PO along a corridor. As you watch you can follow R2's movements until the camera cuts away. If the shot were to continue it seems clear that R2 would have banged into a piece of set protruding from the side of the corridor.
Continuity mistake: When a stormtrooper stands guard by the door of the control room, the door is low enough for someone to hit their head on. But when C-3PO wants to take R2-D2 "down to maintenance", there is plenty of clearance between the trooper's head and the bottom of the door. This has nothing to do with camera angles, as Threepio is the same height as the trooper, and walks out of the room with no problem.
Continuity mistake: Towards the end of the film, the Death Star rounds the planet towards the moon in order to destroy it. The movie continually reverts back to the Death Star where a commander informs us of the time until the Death Star is in range of the rebel base. It will then show the panel with the Death Star's co-ordinates and how long until contact. However, it does not count down in minutes, it counts down in seconds. E.g the commander will say "40 minutes till contact" yet the screen will start at 40 seconds and count down, 39, 38, 37. Regardless of whether or not they use the same time system as us, the time would have run out far too quickly.
Continuity mistake: During the battle between Obi-Wan and Darth Vader, there's a scorched slash mark on the wall to Obi-Wan's right before either saber makes contact with it. A few seconds later Darth slashes his saber in exactly that spot (we can see the scorch mark again before he hits it).