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 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 Richard first wakes up after travelling through time, he's supposed to be lying on a couch. Yet there is a wall behind him. It's blatantly obvious that it's the same shot from the modern bedroom, and all they did was change the lighting. (00:33:45)
Revealing mistake: The door to the weather observatory shows that it is a set by the lack of a complete door frame at the bottom which would let rain and other elements in under it.
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.
Revealing mistake: When Hawk is enchanting his fathers sword he holds the "mind stone" in the palm of his hand and you can see a wire attached to each side of the stone. A few seconds later and, of course, it "magically" lifts from his hand. (00:03:14)