Continuity mistake: When Frank slams his car into Ray's fence, the Volvo sustains body damage on its left side near the headlight. This damage disappears in later shots. (00:06:15)
Continuity mistake: When Lucy is stuck on the floating bed the pillows are visible and when Ray helps her down the left pillow sham is lying flat. However, when the bed lands all the pillows and shams are upright and neat. (00:12:35)
Revealing mistake: In quite a few shots it is obvious that Michael J. Fox's dark-haired stunt double drives the Volvo or does particular stunts. (00:06:15)
Character mistake: At the Gazette office, as Ms. Rees-Jones watches, Steven scrolls up the next front page of the Gazette on his PC and under the photo of Chuck Hughes it reads, "...dead at age 37." However, when Frank gets into his car after being kicked out of the cemetery, under the current Gazette headline it reads, "30 yr. old Chuck Hughes who died of a mysterious heart ailment..." (00:03:10 - 00:05:30)
Continuity mistake: When Frank arrives at the Lynskeys to take care of their ghost problem, he drives onto their lawn again. In the wide shot he takes down a piece of the picket fence, which falls squarely on top of the little statues, including little Bonzo's grave, and proceeds to drive toward the house. However, the next close-up is of the statues, who are still standing, and as the car runs over them the picket fence does not slam down on them like in the wide shot of the 'same' action. (00:13:25)
Continuity mistake: At the police station, when Agent Dammers sticks his badge in front of Sheriff Perry's face, the position of the badge in his hand differs in the shots facing Perry and the close-ups of the badge. (00:56:10)
Visible crew/equipment: During the scene where Frank's ghost pals haunt Lucy and Ray's house, Ray begins hitting a moving Raggedy Anne doll that is near them on the ground. Look closely - behind the doll you can see a black bar that is mounted to the ground, causing the doll to jump and move. (00:12:55)
Continuity mistake: After Frank 'bumps into' the hearse leading the funeral procession, he sees Ray's ghost running up the street towards him. In Frank's front close-up as he raises his arms in shock, the whicker baskets in front of the pet shop are on his left. As Frank hits the ground the baskets are beside him and they are arranged quite differently. (00:26:15)
Continuity mistake: When Frank drives over and crushes Ray's little gnome statue, as Ray shouts the subtitles read, "Budzo! Oh, my Budzo! My Budzo!" However later in the film the gnome's grave marker actually reads, "Bonzo." (00:07:05 - 00:13:30)
Visible crew/equipment: When Frank is walking down the street, after he walks into the pierced man in the grim reaper T-shirt (Peter Jackson in a cameo) when he walks across the street when he gets hit by the black hearse, the camera man, the camera and a few crewmembers are visible in the car door.
Continuity mistake: While Lucy is on the floating bed, only the floral blanket that Ray tossed is on the floor. After Ray helps Lucy off, they sit together across the room and in the next shot when the bed lands, the floral blanket and now a pink blanket are on the floor near the bed. When Lucy screams as Raggedy Anne pulls on her, the two blankets are visible across the floor and their positions differ. (00:12:45)
Continuity mistake: When Lucy watches the video about the history of Johnny Bartlett, the sweat stain on Ray's shirt changes in the following shots. (00:11:30)
Continuity mistake: During the dinner with Lucy, Frank goes to the lavatory to dry his pants and when he pulls on the paper towels more than a foot is left hanging out the bottom of the dispenser. However, in the following shots it's either nothing or a some of it sticking out of the dispenser. (00:37:00)
Continuity mistake: After Mrs. Waterhouse says good morning to her children, in the wide shot she walks to the coffee table to get her mail. In the next close-up, a couple of things disappear from the table, as well as the pillow on the floor, which leans against the couch behind the table. (00:23:00)
Continuity mistake: When Patricia is in the kitchen, the ghost wreaks havoc and when she gasps at the exploding stove the refrigerator is visible. In the next shot when things tumble down from the top of the refigerator as it moves away from the wall, the shadows on the wall are completely different. Then the corner cabinet door under the sink opens fully, however, in the shot from under the table as she dives under, the corner cabinet is closed. (00:01:55)
Continuity mistake: When the 3 "flying" babies crash into their mother, look at the one in the red clothes. In the wider shot it has a lot of dribble on its chin, but this vanishes in the closer shot.
Continuity mistake: After Frank takes the urn from Lucy, he reaches the bench near the chapel and a wood chair lies on its side beside the bench. After Dammers catches the urn, that chair is now upright behind Frank. (01:34:55 - 01:35:50)
Visible crew/equipment: When Frank is in the freezer in the hospital laboratory, as Lucy and Agent Dammers fight over the door latch, the brief reflection of a crew member wearing red is visible in the large polished stainless steel hinge on the door. (01:14:10)
Continuity mistake: Running from the ghost, as Patricia crouches behind the couch at her home and shouts, "Please don't hurt me!", the throw on the couch and the pillows change positions between shots, before she falls onto the couch, as well as the pillows behind her head after she falls onto the couch. (00:01:15)
Continuity mistake: When Frank walks in through the Lynskey's front door he passes a table with assorted items, including a bouquet of red and yellow flowers. When Frank leaves their house, the positions of some items differ and the bouquet is arranged differently. (00:13:30 - 00:17:10)
Chosen answer: For the most part, the actors playing the ghosts were shot separately on blue-screens, and then comped into the scenes. (By removing the blue background through a process called "color keying", and placing them over the scenes) They were simply given a blueish glow and made semi-translucent to complete the effect. It was pretty cutting edge back in the 90's, but nowadays, it'd be very easy to make the exact same effect using a simple program like Adobe After Effects.
TedStixon