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.
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.
Continuity mistake: After Barry has jumped into the water reclaim the crown, he comes out of the water with a perfectly clean shirt but in the next shot the blood is back on his shirt as expected. (00:22:50)
Visible crew/equipment: If you look really close in the background as the killer throws Cici off the balcony, you can see someone sitting in a tree, wearing black, with a camera. (00:33:35)
Continuity mistake: Ripley kills the alien in the corridor after it has killed the first member of the Betty crew but there is no melting of decks or bulkheads from the creature's acidic blood. Also, the Betty crew seem unaffected by all the acid. (00:46:00)
Factual error: The child Lily grabs an apple from a tree, the tree is an oak. Oak trees don't fruit apples.
Continuity mistake: Much of this movie was shot in Luxembourg, not in Paris. This is obvious on several occasions - the road signs are clearly not like the French standard. You even see a sign to »Trier (Trèves)«. In Paris, there would be no signs to this German town...and even if there was, these would say »Trèves«. The buses also have French registration plates but are from Luxembourg companies.
Continuity mistake: When Jack is leaving the shed with the bug bomb, the canister switches from being under one arm to the other.
Continuity mistake: During the scene when Martin and Cray are in the morgue, Cray throws the baseball bat at Martin. When Cray throws it it is upside down but when Martin catches it, it is rightside up. However, you never see the bat flip.
Continuity mistake: In the scene where Chyna decides she needs to fall down the stairs to break the chair she's chained to she's supposed to be handcuffed. As she starts to fall and tumbles down her hands are not handcuffed and fling around wildly.
Continuity mistake: When Wynn is talking to Al about the mission to blow up the plant, Wynn puts his cigarette out in the ash tray in the scorpion bowl and there are 4 butts in the ash tray, but a minute later when the camera shows the 2 scorpions fighting, the ash tray has no cigarette butts in it. (00:11:19)AzN InVasian
Continuity mistake: Throughout the entire movie the size of the Event Horizon's interior versus that of its exterior is repeatedly off. Evidence of this is seen mostly with scenes that take place in the main access corridor. First off, it is made to seem that the ship has one central connecting tube, but in the exterior shots there are several tubes that make up the middle of the ship. This is pointed out when Miller is making his way across the ship to get to the air lock that Justin is about to open. Second, the length of the tube (heck even the whole ship) is too small in relation to how the ship appears from the outside. This is pointed out in a few different places in the movie - when the crew is up on bridge, then race all the way to the airlock in the middle of the main access corridor, where Justin has just closed the inner door and when the doctor is asked to go grab his med kit from medical, which is across the ship and he is gone only a few seconds, and also when Miller is running though the corridor to activate the explosive charges. Since the ship has no faster means of transportation, such as turbolifts or a tram system, they could not be covering the distance they appear to be covering in the movie.
Continuity mistake: After the explosion in the laboratory, Josh is laying on the floor, injured. His face is covered in blood, however during the scene the amount of blood on his face keeps changing. In close ups of his face his lips are free of blood, but in wider shots his lips are covered in thick amounts of blood.
Continuity mistake: In the end when the Kothoga is on fire and chasing Margo, it catches up to her in moments. However, everytime it dramatically changes angles, the Kothoga appears a lot futher away than it was previously, but soon after catching up once again. Noting her progress in the room, this situation is not simply replaying the same scene from different angles. Plus when she gets to the water tank, she has plenty of time to spare to hit a lever, climb the device, and jump in before the Kothoga looms overhead.