Revealing mistake: When Captain Needa is killed by Darth Vader because they lost track of the Millennium Falcon, in the background, two guards come to take him away. You can clearly see the dead captain get up almost by himself. (01:10:50)
Revealing mistake: In Houston, when a man is thrown through a truck, notice the ground he falls on: The sand is leveled higher than the rest of the road around, obviously to hide a landing mat. Furthermore, after the fall the man turns around and he's got a bulgy square on the back to help for a safe stunt.
Revealing mistake: When the sheriff's car is flipped upside down, the sign behind the car is upside down too, so you can tell the car isn't really upside down.
Revealing mistake: When Jake and Elwood are driving through the mall, they leave by driving through some store, if you watch as the people run to get out of the way, a black man with an apron on runs right into the camera. (00:31:40)
Revealing mistake: When Biro stabs the Imperial soldier with his sword, it's obvious that the sword is angled to miss his body. (01:30:50)
Revealing mistake: When Tony is having his first fight in the embassy, it is obvious that most of his punches do not connect at all. The people he supposedly hit still react as though being hit, and the sound effects of a fist hitting a jaw are still there, even if Tony misses by several inches.
Revealing mistake: It's obvious that when Clyde disassembles the car, the car has been pre-disassembled so Clyde would have an easy time taking it apart. Specifically the doors and trunk lid.
Revealing mistake: Right after Father Alvito hands Blackthorne the Portuguese-Japanese dictionary, the Jesuit priests leave Blackthorne and his entourage to continue their journey onto the port of Nimazu. You can see the orange-robed clerics walk along a track that was obviously used by wheeled vehicles. You can see grass growing in the middle of the dirt road and none in the grooves. But in an earlier scene Father Alvito stated that only the Emperor was allowed to drive in a wheeled cart which he only did it on rare occasions for ceremonial purposes and for short distances as this would otherwise damage the roads (as the grooves testify). (01:28:00 - 01:30:10)
Revealing mistake: When Terrible Tommy has Rosa in an airplane spin her hair suddenly gets thicker and her legs get thicker, indicating this is Rosa's stunt double.