Continuity mistake: The distance between the picture hanging on the wall and the light switch wire often changes through the movie. Look at the distance between the two when Adam walks past to throw the spider out of the window. When Barbara pokes her head into the room in the following shot to give Adam his present, the picture now hangs right beside the light switch wire. (00:02:35)
Continuity mistake: When Barbara tears the top of the wrapping paper off of the present (tube of wallpaper) Adam bought her, in following shots the way the paper is torn and the way it hangs, changes. In the very next wide shot the whole of the wrapping paper is suddenly off of the tube of wallpaper, without enough time given for Barbara to have pulled it off. In following shots Adam and Barbara kiss and cuddle on the couch, and in one shot you can see that the wrapping paper had reappeared, and is still wrapped around the tube. (00:03:00)
Revealing mistake: At the start, after the car veers away from hitting the dog and comes to rest teetering on the edge of the bridge, you can see the quick release wire cable that was used to secure the car to the bridge. It's also very visible when the car is sinking into the water. (00:07:50)
Revealing mistake: After the scene where Barbara's fingers catch fire, the Maitland's walk down the hall (and Barbara says "I'll make us some coffee), and in the picture hanging on the wall to the left of the screen, we see their reflections. They shouldn't have reflections, as proved by the mirror. (00:08:30)
Revealing mistake: When Adam, who should have no reflection, walks out of the door to go retrace his steps, he is really clearly reflected in the big glass panel in the door. Then after Barbara pulls Adam from the SandWorm land, they walk back into the house through the same doors, and are both reflected in the glass panels of the door. So much for ghosts... (00:08:50)
Continuity mistake: When Alec Baldwin tries to leave the house and ends up in the sand world for a few seconds, his wife says that he was gone for two hours when he gets back. When the wife is sent to the sand world for a minute at the end of the film, she returns to the house only a few minutes later. (00:09:00 - 01:21:00)
Revealing mistake: When Barbara is moving the little plastic horse in front of the mirror to prove that she's invisible, the "reflection" of the horse is not synchronised with the actual horse. (00:09:10)
Revealing mistake: In the scene where Barbara is showing Adam that they have no reflections by moving the horse in front of the mirror, Adam's reflection can be seen in the windows in the background. (00:09:10)
Continuity mistake: When Barbara shows that they have no reflections by moving the horse in front of the mirror, Adam is seen waving his left hand (in the over-the-shoulder shot) and it cuts to a longer side shot as he's finishing waving his RIGHT hand. (00:09:15)
Visible crew/equipment: Barbara shows Adam their lack of reflections, then points out the book entitled "Handbook for the Recently Deceased" and its publisher. At the very start of the next shot in their bedroom, we can see the reflection of the moving boom pole/mic on the window above the bed. (00:10:10)
Continuity mistake: When the house starts shaking, we see a shot of Adam roll over in bed with a blanket wrapped around his body. In the next shot the blanket is in a totally different position around him. (00:12:45)
Continuity mistake: When Adam and Barbara are sleeping, they awake to a sudden commence of the whole house shaking. There is one close shot of the items on the mantelpiece. Watch the items. There are reels of cotton on the centre of the mantel which vanish between shots, and in the wide shot a book has appeared in front of one of the photo frames, which wasn't there beforehand. (00:12:50)
Continuity mistake: When the Deetz family first check out the house, Otho shakes up a can of spray paint, takes off the cap, and hands it to Delia. When it cuts to the next shot, you can see Delia take off the can's cap again. (00:15:30)
Continuity mistake: When Delia spray paints the word “mauve” on the wall, between shots it is apparent that the script of the word changes. One example would be that in the first shot the tops of the letter “M” are pointed, like triangle tips, but in the next they are more rounder. The writing also moves lower on the wall. (00:15:50)
Revealing mistake: When Delia and Otho go upstairs, Delia takes her can of spray and writes the word "mauve" on one of the walls. The faded marks of mauve spray paint are quite evident on the wall as she sprays the word, which reveals that this was not the first take of the scene. (00:16:00)
Continuity mistake: When Otho is going through the house suggesting changes he is wearing white sneakers in one room and red ones in the next. (00:16:25)
Continuity mistake: When Adam and Barbara try to scare the new residents out of their house, Barbara holds up Adam's head by the hair. He has glasses on and they are up on his nose where one would wear glasses. However, the next shot is a close-up of the head, and the glasses are down on the end of his nose. (00:16:50)
Visible crew/equipment: When Barbara tries to leave the house and falls into the sandworm's world you can clearly see her knee pads. (00:19:00)
Continuity mistake: During the scene where the new family eat dinner for the first time, there are candles in front of the dad (they are in metallic candle holders). They are in an order like large, small, medium. But in the close up shot of the dad they have changed places to medium, small large. The sizes may be different but the concept of the mysterious shape shifting candle holders is the same. (00:19:55)
Continuity mistake: In the part where Barbara and Adam are asked to draw a door on a wall in case of an emergency, there is already a chalk outline of where a door would be. (00:25:55)
Answer: Italy is the center of the Roman Catholic Church, which includes exorcisms as a real-life ritual. Presumably, ghosts in Italy are at greater risk of encountering trouble in Italy because of this reason.