Factual error: When Janet Leigh is shown lying dead on the floor of the shower, there is a close-up of her open eye. The pupil is contracted to a pinpoint (obviously due to the bright lighting) where it should have been dilated. After the film was released, Hitchcock heard from several ophthalmologists who pointed this out and suggested he use belladonna eye drops in the eyes of "dead" people in future films, as the chemical prevents the pupils from contracting. (00:48:30)
Continuity mistake: The birth of the Predalien in this movie is completely different than it was in the first AVP. The lights on the table are different and the Predalien bursts out differently than in the first film. (00:01:30)
Revealing mistake: In the opening scene where the zombie kills Johnny. When they fall against the tombstone you can tell it is a dummy.
Continuity mistake: When the members of the brotherhood beat up Mani until he is dead, they pick him up above their heads. The tattoo on his torso appears to be on his right side, whereas in previous and following scenes the tattoo is on his left side. That shot is flipped.
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)
Factual error: When they're first entering the whaling camp, a penguin startles Miller. That penguin was a black-footed penguin, which is a bird native to much warmer climates. If that little guy had actually been in Antarctica, he would have died within minutes. (00:20:40)
Continuity mistake: As Brian lands the plane down to Bangor, his headset is on in a frontal shot, but in a reverse shot it isn't. (00:47:05)
Other mistake: Max says that Michael is the "Man of the house" and won't come in until he's invited, which Michael sarcastically does, except Michael isn't the man of the house - its actually his grandfather who owns it.
Continuity mistake: James takes off his tie to cover the cut on Kristen's hand, but when they run outside to escape in the car James is wearing his tie again, then after the failed escape they run back inside the house and James tie is missing. In another scene Kristen goes into the woods to look for James and falls into a ditch, then as she climbs out the tie is missing from her hand, but the next scene it's back in place.
Factual error: A girl is playing with a Tamagotchi virtual pet in the scene set in 1994, but the toy was not released in Japan until 1996 (it wasn't officially available in the USA until May 1997).
Visible crew/equipment: There's a scene in which someone goes into a phone booth to make a call. As the phone booth door closes you can see a reflection of the cameraman.
Revealing mistake: When the lawn mower the heroes send off as a diversion crashes you can see a wire pulling it. (01:01:30)
Continuity mistake: When Constantine manages to get the mirror through the window he falls on his back. To the right on the screen a chair lies on the floor beside a dresser. A few shots later when it cuts to Constantine getting up we can see the chair has changed position as its back now covers the opening of the dresser. (00:08:15)
Revealing mistake: In the part it shows Ash getting sucked into the time portal you can see the wire he is hanging from. (00:02:45)
Continuity mistake: When Kelly is on the boat with Hank and the soon to be headless deputy, her green vest (life-jacket) is fully unzipped. When we see her immediately after she's been knocked in the water, her jacket is zipped almost all the way up.
Character mistake: At the memorial service the principal says that it's been 39 days since 39 loved ones had died. But there were 40 students on the plane and 4 chaperones, making the total 44. Now 7 people got off the plane, which means 37 people related to that memorial service actually died, not 39. Two pilots would make up the numbers, but there would be flight crew too, which still leaves the numbers off.
Continuity mistake: When William Petersen is talking to his kid in the supermarket, the cereal boxes behind him on the shelves change between two shots. The items behind Kevin also change during the scene. (01:09:05 - 01:10:20)
Continuity mistake: In the scene where the townspeople are fleeing to the mall there is a shot of the Deputy driving the car. You can see the top left hand corner of the windshield is covered in green goo, but when you see them parking the windscreen is completely clean. (01:03:35)
Continuity mistake: Rachel (Emily Bergl) is in her kitchen and she has a black and white flash back in her kitchen by the sink. One minute, she has on a flannel shirt, the next its gone and she's only wearing a tank top. A second later, the flannel shirt is back on.
Continuity mistake: In the opening scene, Mort closes the door of his jeep before he goes into the hotel room. You can hear the sound of the door closing and it's visible in the rearview-mirror. As the camera moves out of the room, the jeep door is completely open. (00:02:05)
Suggested correction: The door just didn't actually catch. I've had cars like that, especially during the winter.
Given that we see it stay closed for almost 4 seconds and hear it catch, it's a valid mistake.