Deliberate mistake: At no time can a player on the ice play without a helmet. It may be legal in professional hockey, but never in youth league games, world championships or not (This happens when the goalie comes out of the crease and takes his mask off to shoot his "knuckle-puck", as well as the penalty shot in the first movie.)
Deliberate mistake: In the scene in which Ace is in the asylum, he breaks into a storage closet to view Finkle's belongings that were left behind when he escaped. At first the doorframe is such that the door closes against about an inch of wood, meaning the lock would be behind this wood, so Ace couldn't pry it open. In the closeup, the door's flush against the frame so Ace can use the sign to get between the door and the frame. In the wide shot it's back to how it was. (00:58:55)
Deliberate mistake: Twice in this film Axel is shot at by multiple gunmen using automatic weapons at close range - and they all miss. In the Earthquake theme ride the bullets ricochet of the rails at Axel's feet. Why are they all aiming low? Why don't they raise their aim? In the park outside he hides behind a perfectly ordinary park bench and the bullets hit the wooden slats. Not one goes through the open spaces between them? I know bad guys can't shoot straight in the movies, but this is ridiculous ...
Deliberate mistake: After the trilithium missile hits the sun, it is shown going out in real time from Veridian III. As the planet is relatively earth-like, it is several light-minutes away from the sun. The filmmakers wanted it to be obvious that the missile was successful, so they ignored the speed of light. (01:20:35)
Deliberate mistake: In the scene where the bad guy is attached to the missile and fired, in the split second before it hits the helicopter you can see below it a building called SUN BANK, but the letters are backwards. A close look reveals the likely reason - to the right of the reversed building is one which looks just like the building to the LEFT of the Sun Bank building behind the harrier a few seconds earlier. Most likely they couldn't film the chopper from the right side because there was a building there (the one the camera flies through), so they filmed it from the other side (the same side they'd filmed the harrier from), catching the "Sun Bank" behind, then had to flip it to have everything facing the right way. (02:06:55)
Deliberate mistake: When the recon team head out of the base they encounter a robot. But it is a probe droid, distinguishable by the lack of a cannon on its right arm. The only probe droid that the lab sent out self-destructed back in the 1970s, the rest were all sterilisation units. (00:39:05)
Deliberate mistake: When the crow drops Shelley's ring into Sarah's hand at the end of the film, the sound of metal upon metal is heard. (01:30:00)
Deliberate mistake: After the scene where Snipes gets an ID on Jagger from the little girl, one of the officers calls to inform Busey, "A scar under his right eye", yet you can see him form the word "left". I guess "right" was dubbed in to save a re-shoot.
Deliberate mistake: Eric Roberts certainly knows the secret of eternal youth. In the 30 years since his character killed Sharon Stones' parents to the present day, he doesn't appear to have aged a single day.
Deliberate mistake: At the end, when the applause sign falls on Rocco's mom, it should stop working. (01:10:35)
Deliberate mistake: When Jimmy Dove responds to the bomb in the computer lab at MIT, the camera shows the boyfriend on the floor, dead from a self-inflicted gunshot wound to the head. The pistol is lying next to his head and it is a 1911-type .45 automatic with the hammer down, not cocked. When an automatic pistol is fired the slide automatically cocks the hammer as it moves back. This will happen even if there is only a single bullet in the gun. The hammer should be back in a cocked position.
Deliberate mistake: Vega's claw never actually hits any of the furnace buttons, but it opens up anyway.
Suggested correction: The claw penetrates the panel cover and most likely shorted the wires inside. You don't have to actually press any buttons to activate it if you short the wires.
Deliberate mistake: When Wade "hits" Roarke for telling his parents about the gun, it's very obvious that his hand doesn't come near the boy's face.
Deliberate mistake: While Jimmy and Billy are being chased by the jet skis one of the baddies fires a missile, and when it lands in the water the long shot is flipped, note "AKZO" is backwards. (00:49:25)
Deliberate mistake: During the final battle, at one point Sean kicks Crane off a rope bridge. When this happens, if you look closely you can see the rope railing on the side of the bridge fall away right before Crane falls. It's supposed to look like Crane is falling through the ropes, but they drop just a split-second too early (he's not even touching them when they start to fall), so it was done on purpose and mistimed. (It was likely timed to drop away just a split-second before Crane fell so that the stunt-person wouldn't accidentally get tangled in the ropes as they fell).