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.
If you've ever lived where it snows a lot, you'd know that door catches accumulate moisture (ice) and can open slowly, as it did in this case.
Continuity mistake: In the first scene when the girl is walking down the sidewalk she passes by a female zombie wearing a brown shirt twice, and she passes by a male zombie in a blue and white shirt, and a few seconds later he's with a group of zombies that carjacks her in the woods outside of town.
Continuity mistake: In the story titled "Quebec Province 1975", child witch Lucy gets back at her bullying cousin Angela by shrinking her to the size of a mouse. Minutes later, Angela looks up, lifts her hands over her head and begs for mercy. Obviously Lucy is preparing to step on her. But we see Lucy lifting her foot off the floor several seconds after Angela starts begging.
Plot hole: In the scene where she goes to her house after escaping there is no police tape on the front door even though it is a crime scene. Earlier the police searched and taped her office - it only makes sense that they would do the same to her house.
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: When Wednesday and Pugsley are playing with the guillotine, Wednesday has a scroll in her hands, which she then rolls up. The shot changes and you can still see the rolled up scroll in her hands. However, the shot then changes again and you can now see Wednesday rolling up the already rolled up scroll.
Continuity mistake: When the police car rolls out of the car wash, both passenger and driver's doors are open. When the shot changes to the deputy holding the rifle, the driver's door is closed. In the next shot both doors are open again.
Visible crew/equipment: When the woman is performing an autopsy on one of the dead "creatures" the lights supposedly flicker and turn off. There is a hand visible flicking the switches on the lamp to the right side of the screen. (00:45:40)
Other mistake: When they raise the temperature of the room with the facehuggers in, once the room is at body temperature, they open the door onto the much colder corridor. This would have immediately dropped the temp in the facehuggers' room.
Plot hole: No one wonders what happened to all the staff and patients at that sanatorium? No police ever came there and checked the place out after 30 years? And all the patient records, furniture, etc are still there?
Plot hole: The motivation of the cult in this film - a dark entity trying to birth their demonic god - is completely different from the cult of the original film, which was portrayed as fanatical Christian witch-burners. No satisfactory explanation is given in the film to explain this and in fact the film explicitly implies they are the same cult on several occasions. The explanation that the cult of the original film is some sort of offshoot or different sect of the cult from this film cannot explain this as it is pure fan speculation and conjecture (thus non-canonical) and in fact raises several more plot-holes.
Continuity mistake: After Mac has stabbed the scorpion that was on Dillon's back, he puts on a box and crushes it with his boot. You see a clear picture before he crushes it and then after he lifts his boot away. It is facing a completely different direction than before he stands on it. (00:32:25)
Continuity mistake: When Frankie is about to receive the first stigmata (when sitting in the bath), a pigeon suddenly flies up. When she takes a piece of a feather that flew into the water, you can already see stigmata marks on her right-hand wrists.
Audio problem: Just after the car crash, when the zombies are taking Starla, Bill and Kylie yell after her, but they call her Carla.
Factual error: The actual Tsavo lions responsible for the killings had no manes - see for yourself; they are on display at the Field Museum in Chicago. [The filmmakers employed artistic license in using maned lions. They were also certain to include - at the very end of the movie - footage of the real Tsavo man eaters, as they appear in the Field Museum.]
Visible crew/equipment: In the scene where Burt and Spider take the cop car to go get help, after they back up from the group of zombies in the street. You can see a cameraman in the front passengers seat holding a camera with a blinking red light on his shoulder as they drive away.
Visible crew/equipment: Watch the scene where Frank gets killed. In the last shot of this scene, we see a soldier standing over the dead body. Keep an eye on the right side of the screen as the camera slowly moves away and you should see one of the cameras and a cameraman on the ground next to a large metal object. (01:06:25)
Continuity mistake: In the scene where Thora Birch's character goes to a café with her psychologist, the psychologist takes a bite of a cake and puts it back on the table. In the next scene, the cake has not been touched.
Audio problem: A soda can that is supposed to be full hits the man. When the can hits the ground you can hear that it's empty.
Other mistake: Towards the end of the film, after Snipes beats up of a lot of vampires, Whistler throws Blade's sunglasses to him. They show him throw them in one shot, then in the next shot they show Snipes catching them. But look in the background at Whistler, he doesn't have the glasses, but is moving his arm like he is throwing them. The glasses must have been computer animated, and bad editing contributed to this mistake. (01:37:34)