Plot hole: The convicts remove the radar transponder from the Conair aircraft and put it aboard a tour plane to distract their pursuers. That won't work. By law the tour plane will have a working radar transponder of its own, and two working transponders that close together will show up on radar as a collision. Air traffic controllers would immediately alert emergency services who would, obviously, wonder how two aircraft that had collided had managed to stay in the air. Nobody disconnects the first transponder - Pinball carelessly tosses the second transponder under the rear seat of the aircraft (the implication being that it continues to operate, perhaps on backup battery power). He doesn't disconnect the original transponder either - Swamp Thing, a skilled pilot, does that. There is no time for him to do any of this before he is stopped by the female security guard anyway.
Revealing mistake: When Austin enters the bathroom at the casino, keep your eyes on the door during the scene - it opens by itself before closing. (00:31:10)
Revealing mistake: In one shot when the boat is pulling away from the waterfall, you can clearly see that the shot is the same one they used earlier in the movie. The water from the waterfall now is going up the cliff! They have just put it in reverse.
Continuity mistake: When they are looking at the house and they get out of the car, the one man on the passenger side leaves his door open. When they walk to the side of the house and come back to the front, you can see the car in the background and the door is shut.
Factual error: The Russians stopped using steam locomotives in the 1970's. So bringing one out of retirement in 1997 to haul nuclear warheads would mean that your highly secret nuclear train would be well known among rail enthusiasts for weeks before.
Factual error: The lake that Jack told Rose he went ice fishing on when she was threatening to jump is Lake Wissota, a man-made lake in Wisconsin near Chippewa Falls (where Jack grew up). The lake was only filled with water in 1918 when a power company built a dam on the Chippewa River, six years after the Titanic sank. (00:39:05)
Deliberate mistake: Leaven spends too much time thinking about if 645 and 372 are prime numbers to be believable. But she knows the factors of 649 and the result of 26 to the power of 3 almost immediately. Plus anyone with any maths knowledge whatsoever would know that any even number (or one divisible by 5) can't be prime, so 645 and 372 could be dismissed without even thinking about it.
Plot hole: When Andy turns into a werewolf, he kills both Amy and Detective Benbou. Later in the morgue, Amy tells him because of this that she is forced to become his "rotting sidekick." If this is completely true, then Detective Benbou should also be following Andy around but he isn't seen after Andy manages to escape from the morgue.
Continuity mistake: When Chris Farley is pretending to be a Chinese cook at that one restaurant, cooking, the brown spot on the stove keeps on changing size.
Continuity mistake: When Sam and Anton are finished fighting (Anton is in an upper-body cast), the arm support on his right keeps changing. First it's a short piece coming from the elbow, then it is a long piece coming from the side, and then back again.
Visible crew/equipment: When Nisi and Mickey first walk into the bathroom Mickey asks why there are two toilets, and in the next shot the microphone pops up into view at the bottom of the screen.
Continuity mistake: Just before Demi Moore is about to get her head shaved she sees the base commander about equal treatment, and we notice very visibly that O'Neil has one side of her face bruised and all red and swollen. But in the next scene, which takes place moments later, when O'Neil is shaving her head, her injuries are all gone. Where did they all go to?
Visible crew/equipment: The cameraman is visible in the reflection of window while Holden is walking back to his car in the rain.
Revealing mistake: When Fletcher is beating himself up he goes into a stall and squishes his head with a toilet seat. You can see that the white part underneath is made out of foam because it keeps squashing down.
Factual error: The plastic explosive used on the cockpit door was C-4. When shot (as shown), C-4 does not explode; it requires the use of a detonator.
Suggested correction: You can see him applying a detonator prior to him shooting it.
If he applied a blasting cap (detonator) he should have used it then. Just putting a detonator into C-4 doesn't all the sudden make it vulnerable to being shot, he would have to actually hit the blasting cap's wire, which is about 5mm thick and relatively short (and it would have to be one that's sensitive to gunfire). Not a very probable shot, even less so when he doesn't even look when he shoots.
Plot hole: In the scene where Ashley Judd runs away from her attacker and falls into her aquarium he has moved to the bottom of the stairs - there is no way he would have been able to move that full fish tank. It looked to be about a 30 gallon tank - it would weigh about 400 pounds with the stand and even if he slid it with some superhuman strength, glass tanks are notorious for shattering when you move them full. Plus it would've made enough noise to wake the dead - no way she wouldn't have heard it.
Plot hole: In the final showdown, when Bond is fighting with Stamper, the girl is wrapped in a chain, hanging from a crane and dropped into the sea. After the boat blows to bits, the chain continues to hang down, even though there's nothing holding it. It even keeps hanging after Bond's swum down to untie her. What's keeping it there? Do all stealth battleships come with buoyant chains? With both arms at least partially free, why doesn't she just climb back up the chain?
Continuity mistake: When they are running the obstacle course, the amount of hoops in front of the girls changes from five, to two, to five again.
Audio problem: When Will Smith is looking at the two space ships at the MIB headquarters, if you look in the background Zed and K are there typing on the computer. But if you look closer you can tell that they're not even touching the keyboard and the sounds are just added into the movie. (01:16:00)
Continuity mistake: When the kid rescues Bud from his former owner, Bud's paws become all muddy when the faucet breaks. In the next scene they are running down the road and Bud's paws are clean.