Deliberate "mistake": When Eddie and "Jennifer" are walking around the house alone, "Jennifer" is trying to tell Eddie that she's really Sara. But By the time she is explaining that her name is actually Sara and not "Jennifer", Eddie has disappeared. She doesn't find him until later... But from the moment she finds him (and he is talking to her) he calls her Sara... but he never actually heard her say that. He was gone. Also, after they all get back together, a few of the other people start calling her Sara as well....but no one actually heard her say that her name was Sara.

Revealing: When the house has been locked down at the beginning of the film no moonlight could come in, however when the guests are being shown the coffin with the guns in there is a shaft of bright moonlight shining on to it.

Revealing: In the scene where the girl is going to shoot Vincent Price watch closely as she pulls the trigger. You can see the wires pulling the gun from beneath to give it the realism of the blast.

Continuity: Right after Evelyn gets electroshocked, Blackburn takes off her mouth guard and a pool of blood leaks around her lips and down the side of her cheeks. In the next shot, there is a little bit on her lips, and a lot down the side of her cheeks, and several shots later she is seen with only a little dribble down her cheeks and none on her lips.

Factual error: In the scene where the cast find the guns in the tiny coffins, they mention that it is not possible to tell if they are loaded because the clips are welded. Being semi-automatic pistols, simply pulling back the slide & ejecting the first round would have easily determined whether live or blank rounds had been loaded.

Deliberate "mistake": In the scene about the Terror Incognita roller-coaster, when the rails break, they have ragged ends at the gap; after the first roller-coaster train derails, the rails move together again to close the gap and allow the second roller-coaster train to pass safely; but as you see the rails move together again, they now have neatly cut ends at the gap, not ragged ends. A deliberate error to mislead the audience, but an error nonetheless.

Continuity: When the guests are shown the guns in the casket, upon the first look inside they are not straight or in a perfect line, but in the close up shot they are straight.

Continuity: In the scene where Evelyn and Steven are fighting, he has his hands around Evelyn's neck. Her hair is next to Steven's hand, then it is away from it. This changes from shot to shot.

Continuity: When Sara and Eddie are in the saturation chamber thinking that Price killed Blackburn, they open the chamber and discover the body of Blackburn. When the body falls out the arms and legs face towards Sara, then when they look at it on the floor it is now facing the opposite direction.

Continuity: At the start of the film when we first see Evelyn enter the house on haunted hill, she drops her briefcase at the door right on some kind of design on the floor, in the following shot the briefcase has moved forward some distance from where it was in the previous shot.

Revealing: In the opening scene of the film we see the patients of the institute smash through a cubicle where a guy is, watch closely (preferably in slow motion or frame by frame). The glass breaks away very very easily, obviously some kind of special easy-to-break glass used for this scene.

Factual error: At the end of the movie when the survivors escape the house they see the sun rise on the horizon. The problem? They are in California and the sun comes up on the east coast.

Visible crew/equipment: When Sarah and Eddie return to the saturation chamber after losing the other two, the camera shot is high up looking down into the room from a corner. In the upper right hand corner above the saturation chamber you can see the microphone fully in frame and "hovering" as they re-enter that room. It is also there a second time after the camera angle changes.

Continuity: At the start of the film when Pritchett has led them all up to the house. In one shot we see Blackburn saying his line, "Wheres our host, the fabulous Mr Price?" look behind him at Pritchett he has his hand up to his glasses, then in the following shot he has his hand down by his side.

Factual error: At the opening scene of the film when one of the insane people of the institute shoves pencils into the guys neck, the pencils we see are not long enough to go right through his neck. The insane patient would have to be holding the pencils inside the guys neck for them to go right through him.

Factual error: Pretty precisely at 46:20, in the scene where Eddie and Sarah lost sight of each other down in the cellar, Sarah follows the apparition she thinks is Eddie. While doing so we see writing at a wall: "stehen nicht bei türen oder fenster wann dem Alarm gehört war" . The sentence contains so many mistakes that it's difficult to understand, but it roughly translates into "don't stand in doorways or windows after hearing the alarm". But it's a cellar, so there shouldn't be windows, and if the reason for the warning is the locking device: that closes only exits, and there are none of those in the cellar.

Continuity: In the scene where Chris Kattan is sitting on the couch telling everyone that they are going to die and just before Eddie slaps the glass out of his hand, you see a back shot of Chris pouring the last of a bottle into a glass, then it cuts to the front and shows him pouring it again.

Continuity: When Eddie and Sara are walking around in the basement, Eddie splits up from Sara, and then Sara spots him standing next to a doorway. In the first shot Sara walks around the corner and spots Eddie, yet in the following shot Sara is actually leaning against the doorway.

Continuity: When Sara follows the imaginary Eddie into the room containing the big tank of blood, in one shot we see that Sara passes a glass medical cabinet, and in the following shot she is seen passing it again.

Continuity: If you watch the deleted scenes on the DVD, there's a scene where it shows the real Jennifer talking to the dead asylum owner about her getting the house in a will. When she walks in and screams and the camera goes to the guy it shows her walking in again!