Continuity mistake: In the very first scene when Seagal first gets off the helicopter we see that he's wearing a navy blue shirt tucked into his jeans. In the next shot he's shown wearing the yellow suit but instead has a white shirt on underneath instead of the navy blue one.
Continuity mistake: In the scene when Nick Nolte is arguing in the parking lot, he unlocks his car door, but his window is rolled down in the same scene.
Visible crew/equipment: A boom mike is reflected in the car window, when Alex pushes Hugo's car into the lake.
Continuity mistake: Even though the moon plays a leading role in the movie its phases get mixed up in a big way: Before Will has his first night out as a semi-wolf there's a shot of a half moon. That's not only just a few days after the full moon when he was bitten, but it's waxing to boot. In the next night, after Will calls Laura, apologizes for his vanishing, and asks her out for dinner there is another shot of a slightly fuller moon, but now it's waning. However, two days later near the end, when Will is locked up in the barn, the moon is full again. (00:46:40 - 01:05:05)
Other mistake: The kids dare each other in a decrepit water tower which is mysterious in a number of ways: 1) Draining the water causes a powerful vortex, but the water level is not going down. 2) No one seems to work the bottom valve, but the vortex comes and goes. 3) It is absolutely impossible that anyone could swim through such a vortex, but Stu does. 4) The rotten roof breaks under the weight of little Billy (the ice-cream excess?) but carries his brother who weighs about 4 times as much. (01:27:00)
Continuity mistake: During the trial when Beverly is cross-examining Mrs. Ackerman, her neighbor, she asks if those were her scissors found sticking out of Mrs. Sterner's stomach. That's not where the scissors should have been found. After stabbing Mrs. Sterner with the scissors, Beverly pulled them out and threw them at the husband twice, both times they ended up sticking in the walls, and that is where the scissors would have been found when the police arrived.
Continuity mistake: When Schwarzenegger's urine is tested for pregnancy, the colour of the contents of the vial does not stay the same for two consecutive shots.
Factual error: We're told they carbon dated the gold to determine its age. Problem is, the gold hasn't aged by the normal processs - as it's been brought forward in time it will appear to be extremely new. As such carbon dating wouldn't work. Also, carbon dating only works on things that were alive and absorbed carbon-14; gold, having never been alive, could not be dated this way.
Factual error: What on earth is the conductor at the premiere of the 9th doing with a baton? This was not used until around 1849, and the premiere of the 9th is in 1824.
Continuity mistake: In the scene when Rudy is holding a colt python to the hotel owners nose, in the next shot, the gun suddenly changes to a smith and wesson revolver.
Continuity mistake: In the last game of the movie you can see that Ray Mitchell (Angel Player) hits a home run to tie the game. If you look you can see that the home run ball goes over the fence and out of the stadium but then after they change cameras to Ray and then back to where he hit the home run it shows a man with the ball in his hand as if he caught it.
Other mistake: When Lamont walks into the alley to avoid being followed by one of Khan's warriors, he makes himself invisible, and his shadow vanishes as well. It's well noted at the beginning of the film that his shadow is always visible even if he isn't. Therefore, his shadow should still be seen on the ground and give him away.
Continuity mistake: When Tommy Lee Jones pops into his local Irish boozer for a pint of what is supposed to be Guinness, it is clearly not a pint, it is clearly not Guinness (flat Coke, more like), and the level of said beverage in the glass fluctuates wildly and out of synch with TLJ's swigging.
Continuity mistake: Immediately prior to Preston and Shay dancing in the fountains, Shay is wearing high heels. While dancing in the fountain, she wears flats. After leaving the fountain she is once again wearing high heels.
Factual error: There is a shot with Wesley Snipes and Gary Busey aiming one another just to pull the triggers and discover that the guns are out of ammo. In fact, after the last shot (of the pistol, not the movie) the slide of a semi automatic pistol is retained open by the empty magazine, and doesn't return forward as we can see in the shot (of the movie, not the pistol). The reverse mistake is very common in movies, when the armorer loads just one round to be shot (in the movie as well as the gun) and the actor keeps fighting or menacing with an unloaded, breech opened gun.
Visible crew/equipment: When Li's sons is doing "pushups" on one finger while flying up into the air you see the wire attached to him. (00:29:50)
Factual error: When Julia Roberts drives away from the building where she finds the dead body of the boy with "LD" written on his hand, it is raining heavily. Yet, as she accelerates, there is an extended sound of tyres screeching on a dry surface.
Revealing mistake: When Beauty is nursing from his mother, you can see that the foal used was a filly and not a colt when "his" tail swishes from side to side.
Continuity mistake: At the final fighting scene (David Sloan vs.Tong Po), you can see that Tong Po's hair (a half shaved head with only a ponytail on it) is as fake as it can be: everytime when he moves his head a bit to rough around (sweeping his ponytail around while fighting) clearly shows that he's wearing a special kind of wig attached to his head. That 'wig' is so badly attached that it looks like he's got rimples on the back and on top of his head.
Continuity mistake: In the bus scene, when Stallone goes on the bus the number is 9372, when he kicks the bad guy out of the window the number on the bus' side is 9369.