Continuity mistake: In the beginning of the movie, when the little girl is falling, they film her falling all the way down backwards. When they flash to the young Simon's face and the priest and back to the girl she lands face down.
Continuity mistake: Toward the end, Carmen Ibanez gets stabbed through the shoulder when she is brought before the big master alien thing. If you were to sustain such an injury, there would be so much swelling, not to mention just destroyed tissue, that you wouldn't be able to move that arm for weeks. Yet a few minutes later, she is seen hefting around a very large assault rifle, and seems to have no difficulty. I guess it's a pretty standard action movie "heroes can temporarily ignore injury in order to save the day" kind of oversight, but it just seems exaggerated in this case, considering how severe the shoulder trauma looked. (01:48:15 - 01:53:40)
Continuity mistake: When the T-rex is in San Diego and is about to smash the bus, the driver tells everyone to get to the side. There is a guy in a seat right behind the driver, but when we go outside the bus just before the T-rex crushes it, that guy is no longer there. (01:52:05)
Continuity mistake: There's a scene where Ellie sleeps with Palmer, then gets up quickly to go to the lab. In her haste, she departs whipping on a shirt with no bra. If she had a bra inside that tight T-shirt the contours of the cups and straps would be visible and we would see her fitting and fastening it, instead she steps outside where suddenly it appears she is now wearing a bra.
Continuity mistake: Just before the diner scene, where the two aliens are discussing the galaxy, we see the outside of the Russian restaurant. The neon sign says "haroshaya" meaning "good" all the way across the window, in the next shot inside the restaurant, the "ha", which looks like the English letters "xo", is gone and the sign is centered. (00:41:00)
Continuity mistake: When Ethan Hawke and Uma Thurman are escaping form the party, the sleeve of Ethan's suit is ripped under the armpits when he hits the cop but in a few seconds you see his sleeve completely fixed. (01:11:40)
Continuity mistake: When the police confront Leeloo on the side of the building, she raises her hands and we can see that they're covered in soot. She jumps off and lands in Korben's cab. When she comes to, she presses her hand against the glass, and her hand is magically clean. (00:32:35 - 00:33:20)
Continuity mistake: When Fred Randall keeps expelling gas, the glass on his helment keeps reappearing and disappearing.
Continuity mistake: When Sean and Tito first drive the Hummer onto the runway, the jet is a mere short distance away, coming towards them. In the following shots, the distance between the Hummer and the jet has increased tremendously, for the ensuing drama to unfold. (00:09:40)
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)
Continuity mistake: In the opening, the camera zooms in on an eye that is a very light greyish blue. The camera then cuts to a man lying on the floor. The implication is that it's this man's eye. However, the man's eyes are brown.
Continuity mistake: When Miss Christina is caressing the Jane Eyre manuscript against her chest the book is open, then stops because she thinks she hears something, but in the wider shot the book is now closed.
Continuity mistake: In the scene where Wayne makes his speech at Szalynski Labs, he pretends to stand in a strange shape. When he does so, his speech cards are facing down. In the very next shot, the cards are facing up.
Continuity mistake: Peter walks into the bathroom holding a box of Chinese and a bottle of wine. He puts them down and hugs Sarah. She falls backwards into the bath and now he too is holding a glass of cloudy looking water. (00:08:25)
Continuity mistake: During the first fight scene, the cyborg hunter has dark markings around his eyes. As soon as the fight moves indoors, the markings disappear completely.
Continuity mistake: When Joe goes to quit, it is late afternoon (it is getting dusky). But when he shows up at Ben's house afterwards to tell him that he just quit, it is lighter, like it's the middle of the day.
Continuity mistake: When Hank Simes reappears in human form, he is wearing a red shirt that materialised with him. But when the blue laser disintegrates him, the shirt falls to the ground.
Continuity mistake: Costume continuity throughout the whole film. When the female scientist gets changed into khaki pants they are tight fitting, they alternate between tight and baggy throughout.
Continuity mistake: In the middle of the hotel fight when Toby and Deliverance go through the door in their hotel room you see the door open and a number of shots impact it. The characters then go through the second of the double doors. This is commented on in the DVD commentary. Not only do the bullets not go through the second door, they don't go through the first. On top of that, you see a shot with the two doors opened, but when the bad guys enter the room the double doors miraculously turn into just one! This layout is then used for the rest of the scene.
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.