Carly's height changes throughout the film. This is explained
in the extras; because Jared Padalecki is so tall, Elisha Cuthbert wore wooden shoes in the scenes where her feet weren't shown. In some scenes, she is up to Wade's shoulder. In others, she is up to his chest.
When Nick gives Carly his shirt, it's massive on her and you can see the side of her bra, later on when you see her, the shirt fits fine.
When Bo is talking to Carly through the truck window he is carrying a container of things, and at one point he throws all of the things on the ground. You can clearly see all of the items strewn across the ground. In the next wide shot, though, all of the items are missing and are never shown again.
When Carly first sees the reflection of the man in the mirror, she is standing directly in front of it. When she is explaining to Wade what she saw, she is alternately standing further away from, then closer to the mirror.
When Carly and Wade are looking around in the House of Wax for the first time, Carly dusts off a section of a mirror. Between shots the mirror goes from having only that small section wiped off to having the whole surface wiped free of dust.
Wax has an incredibly low melting point, so even long before the ending where the wax museum melts down due to a fire, any hot weather should have been enough to melt the museum.
When Carly and Wade first enter the town, they pass a movie theater marquee. The name of the movie that's airing is incorrect and grammatically wrong. The movie is listed as "Whatever Happened To Baby Jane?" The true title is "What Ever Happened To Baby Jane?"
When the wax house is burning down, all the wax coating the figures is melting away at a rapid pace, revealing the corpses underneath. However, Vincent wears a mask made out of wax that only partially melts in the heat, remaining on his face until it is physically pulled off. This wax mask should have easily melted away long before that could happen.
When Bo is strapping Carly into the chair, he starts with her right wrist and you can see her trying to push him away with her left hand, but once he straps her right wrist, both of her wrists are suddenly strapped down.
The green screen CGI effects used on Brian Van Holt when Vincent's face is revealed are off; the scarring on his face moves unnaturally as a result.
When Carly is on the phone trying to reach Paige and Blake, Bo hits the window once without it breaking, then hits it again so it breaks. Later, when Blake is checking the voicemail, you hear the window break the first time it's hit.
When Nick shoots Bo in the chest with the crossbow, he cries out in pain and falls back. However, Bo's lips don't move when he makes the sound.
After the group takes the detour, and they are driving on the back road, there is a shot of the red car from behind. If you look at the very bottom of the screen, you can see the equipment that the car is hooked up to.
When Paige is running towards the stairs in the building, as she nears them you can see someone running left-front of her.
Australian mountains and eucalyptus gum trees are seen in what is supposed to be Louisiana.
During the scene at the campsite close to the beginning, in the morning shortly before Carly goes to the turlet, the birdsong that can be heard is clearly the song of a European robin that would not be found in America.
The group is supposedly heading to LSU's Tiger Stadium. When the GPS is shown, the destination is Memorial Stadium, about 5 miles northeast.
The shadow of the boom mic is visible briefly in the top right-hand corner as Wade enters Dr. Sinclair's office.
When Carly is reading the framed news pages, she reads: «Trudy and husband are expecting first child» while the word «are» is missing from the news headline.