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 Paddy lays dead on the beach holding a barrel, the kids turn him over and a crab crawls out of his mouth. You then can briefly see his nose move like a rabbit sniffling. Also his pupils are narrow, and a the side of his neck has a pulse. In other words, he is very much alive. (00:24:30)
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: When the Marines shoot the Japanese pilot, you can see the wire used to set off the blood bags coming out of his pants leg as he falls. (01:11:30)
Revealing mistake: The cannibals kill Faye, and then decapitate her. Then one of the natives lifts her head up, only to let the wig slide off of the fake head, and reveal a yellow foam head underneath.
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: At the end when Hawk fatally wounds Voltan there is a slow motion shot of Voltan rolling around in pain on the floor and his helmet falls off, revealing his whole face. You can see he is not wearing his burn make-up here. (01:28:16)
Revealing mistake: After the shot that shows Herbie spitting sea water from his exhausts, look at the bumper in the next shot of Herbie, when he gets black smoke from his exhausts. The rust doesn't look real, because they used paint to make it look like rust.