Corrected entry: While the Millennium Falcon is evading Tie Fighters, before they enter the asteroid field, Han and Chewie are in the back working on emergency repairs. Who is flying the Falcon? It wouldn't be on autopilot as they are trying to evade laser blasts. Leia or C-3PO certainly do not have the experience to fly the ship that well. It is also doubtful that the Tie Fighters are taking a break from pursuing them.
Corrected entry: In the final scene of the movie, Chewbacca and Lando have already left and the camera is panning away from the observation window Luke and Leia are standing at. There are some Y-wings and X-wings patrolling for the fleet and the last two X-wings in the shot pass in front of one of the starships and disappear.
Corrected entry: The Snowspeeders, used to rescue Luke and Han and for fighting the AT-AT's, have a serious design flaw. If you watch as the aircraft turns left and right, the ailerons (the flaps used to control the air flow over the wings), lift up and down facing the wrong direction. They lift towards the front of the aircraft, instead of behind. This would seriously disrupt airflow over the wings and create a considerable amount of drag, therefor causing the speeder to slow down every time it makes a turn. Not exactly what you want to happen when fighting AT-AT's.
Corrected entry: During some shootouts, you can se the empty cartridges, (blanks I presume), fly away from handguns. These are probably used to create a muzzle flash for realism, and for the special effects people to identify where and when to put the red laser coming from the guns. I've never seen a laser creating muzzle flash. This can be seen best when Leia, Chewbacca and Lando are fleeing the mining colony, and Lando is siting next to the the Millennium Falcon's loading ramp, firing at Stormtroopers.
Corrected entry: After Luke has been shot down during the Hoth battle and is hanging underneath an AT-AT walker he cuts a hole in the underbelly with his lightsaber causing a massive shower of sparks. As the sparks clear you can see a hand sliding back and removing the section of the walker that Luke supposedly just cut through.
Corrected entry: After Vader kills Captain Needa there are two guards which he orders to him drag out. Look at the Admiral when he is pulled out - his neck is up. That's impossible, he's dead, so his head should be lying to the side.
Corrected entry: Why does Darth Vader keep getting more authority? He defers to Grand Moff Tarkin in the first movie, suggesting he ranks between Moff and Admiral. In the subsequent movies, he is second only to the Emperor. Why? He never catches the rebel leadership and loses major battles he is placed in command of. He suggests treason against the emperor by suggesting Luke help him overthrow him. He keeps letting incompetents run the show and warn the rebels through their stupidity rather than run the operation from the bridge himself.
Corrected entry: Throughout the films only C3PO can understand R2D2 and has to translate for the other characters on many occasions. During the flight from Hoth to Dagoba Luke read a little screen with the translations of what R2D2 is saying. Then when they reach the planet and are both stood on the edge of the swamp Luke can miraculously understand what he is saying.