Revealing mistake: In the scene where David starts the game with Joshua, it asks him what side he wants to be (1 for the U.S. and 2 for USSR). Look carefully at the closeup of the computer screen - his choice, 2, appears long before David actually presses the key.
Revealing mistake: During the big gun battle right before the last fight scene, Riggs is shown driving a forklift, and knocking over some barrels on top of Wah Sing Ku, leader of the Triads. When the forklift does the 180° turn, you can see that it is not Mel Gibson, but an Asian stunt man.
Revealing mistake: When Spitz is stabbed with the pitchfork, you can see the line where the fake chest is. It's a different color.
Revealing mistake: The shot of the two nuclear missiles being launched is used twice, just reversed. They seem to have changed the saturation slightly in one of them to make it look different, but there are identical clouds at the top left/top right in both shots, ruining the trick.
Revealing mistake: When the Pterodactyl is flying around with the egg, its shadow isn't cast as she flies over the trees.
Revealing mistake: When Wick is rubbing his toeless feet, the shot changes so that the camera is behind him and you can see him still rubbing except now you can see that he is simply curling his toes over.
Revealing mistake: From the front view of Karen's gun, you can see empty chambers.
Revealing mistake: Just after Madison says to the Angels, "Looks like one of the three amigos has gone adios" and Drew gets thrown by Madison, Drew hits the wall. For some reason, the camera vibrates.
Revealing mistake: When John, Kate and the Terminator are in the Winnebago, there is a shot that's facing Kate where John says to her that they're going to pull the plug on Skynet and that the bombs won't fall. In this shot, look at John's hair. The green screen is reflected onto it. It is visible throughout the rest of the scene. (01:09:45)
Revealing mistake: In the gun battle following the bank robbery, Drucker fires his shotgun at Cherrito. A female pedestrian in the background (apparently unaware she's in the shot) can be seen acting casually, without any reaction to the gun battle taking place.
Revealing mistake: Halfway through the movie, Alta is swimming in the pond, supposedly nude. However, when she climbs out, she can be seen wearing a flesh-covered swimsuit. (00:45:15)
Suggested correction: Alta never said she was naked. She didn't know what a bathing suit was and Adams assumed she was naked.
Revealing mistake: When the Hulk walks through the stream, the water doesn't react to his feet. (00:59:20)
Revealing mistake: In a scene where the canoes are shooting the rapids through a sheer cliff you can clearly see a stuntman climbing out of the water onto the rock.
Revealing mistake: In one scene, the Penguin is making a "bat" shadow puppet on the ceiling. But there's no light behind his hands. If there's no light, there's no shadow. (01:03:45)
Revealing mistake: Near the end of the film, after the shootout, there's a shot with the camera zooming in on a newspaper at Will Smith's front door. If you pause it right once the headline fills the top of the screen, you'll notice all the paragraphs are just repeated, word for word. Additionally the word "received" is misspelled.
Revealing mistake: This is toward the end of the movie. The scene where Dr. Giggles has a waiting room full of his victims. If you watch closely, you will see the blonde corpse blink her eyes.
Revealing mistake: When Mia is playing softball in gym class, and the ball she hits at Josh hits him in the groin, he actually gets hit in the stomach. (01:24:45)
Revealing mistake: When it shows the video of Tom Cruise on Youtube, on the right side of the screen, the descriptions of the other videos repeat themselves.
Revealing mistake: In the skywalk scene, when McClane pushes the paint stand on the terrorist, it is quite obvious that they use a dummy when the paint stand falls on the terrorist and crushes him. (00:45:05)
Revealing mistake: At the Smithsonian Air and Space Museum, there is a triangular enclosure around Jetfire that amusingly just fades away and vanishes as Jetfire transforms. (01:23:05)