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)
Stupidity: The Death Star comes equipped with a powerful tractor beam capable of capturing a ship the size and agility of the Millennium Falcon. Why don't they use it against the rebel fighters attacking them at the end of the film? Okay, Obi-Wan Kenobi turned it off earlier but I find it hard to believe that someone who has never before visited the largest, most complex space station in the Universe and who was previously unaware of its very existence can disable a fundamental security system but the people who designed, built and run the whole thing can't work out how to switch it back on. They should have no problems with this, considering the fact that Obi-Wan didn't damage it.
Suggested correction: Obi Wan disrupted the battle at a critical time causing much confusion. We could chalk this oversight up to "Fog of War" - that in the heat of battle it's normal for commanders to overlook obvious things and seem to act stupidly. It would also be reasonable to assume that the fighters were too close for the tractor beam emitter to target them.
This scenario would require every single person on the Death Star who was involved in the maintenance of vital defence systems not noticing that one of them had been switched off! Not ONE person noticed? Obi Wan did not disable the tractor beam during "the heat of battle." There was a considerable time lapse between his switching off the tractor beam and the climactic final battle, during which time it would have been switched back on. When the Millenium Falcon leavs the Death Star Han Solo remarks that he hopes that "old man" succeeded in disabling the tractor beam, implying that those on the Death Star would be trying to use it. Even then, they didn't notice it had been switched off? Not sabotaged, not disabled, switched off.
Good point. This was definitely stupidity on the part of the Death Star crew, but not stupid as a plot point. It does happen in combat regularly. In 1987 the USS Stark was hit by 2 Iraqi Exocet missiles after challenging a single fighter. The ships' Close-in Weapons System should have easily shot the missiles down, but the investigation showed that no-one had noticed that the system had not been turned on.
They didn't use the tractor beam when the gang was escaping in the Falcon because they WANTED them to get away. The Empire placed a tracking beacon onboard so as to be able to find the hidden Rebel Base. As to how the Falcon was snagged originally: yes, they had just exited hyperspace, but they were not relatively fast; they were preoccupied with the TIE fighter (incapable of light speed) and the small moon right up to the point they were trapped in the tractor beam (and realizing "that's no moon!"
Suggested correction: The Falcon was travelling towards the Death Star when it was caught in the tractor beam. The tractor beam was properly turned back on by the time it travelled to Yavin. The rebel fighters are too small and quick to be held in a tractor beam and there are so many of them so it would be near impossible to trap enough to make a difference.
As I have already pointed out, assigning technical limitations to a wholly fictional piece of technology is absurd. As to "flying towards the Death Star" - the X and Y wing fighters are shown doing just that. As for being too quick, the Millenium Falcon is decelerating from superluminal speeds when it is captured in the tractor beam. That's pretty bloody fast in anyone's books.
The key phrase here is "fictional piece of technology", there is no way to understand how it works. Any explanations is pure conjecture.
It's flat out stated by General Dodonna in the battle briefing that the Death Star's defenses are based around repelling attacks by capital ships, not fighters. The targeting may not be exact enough.
Actually, claiming a fictional piece of equipment can't behave the way you think it should is somewhat silly. The previous explanation that the tractor beam's limitations were the reason for not using it during the battle makes perfect sense.
Revealing mistake: When the stormtroopers stun Leia, if you watch carefully, you can see that she begins to fall before the beam touches her.
Suggested correction: She could have slipped on the floor. No mistake here.
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.
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.