Continuity mistake: As the earthquake happens and the ghostbusters fall in the crack, the close-up shot shows Ray holding his gloves, yet in the immediate cut away he is wearing them. (01:20:30)
Continuity mistake: In the scene where the earthquake begins, the Ghostbusters fall into a hole. They're in two rows - in the first row are Venkman and Ray and in the second row are Egon and Winston. In the following shot, it is now Ray and Winston on the first row and Venkman and Egon on the back row. (01:20:30)
Continuity mistake: After the pavement cracks and swallows a police car, the chunks of broken pavement next to the car differ between shots. From a back view there are smaller pieces, but from a front view they are a couple of big and long chunks. (01:21:00)
Continuity mistake: The Stay Puft Marshmallow Man has a red bow tie on as he walks down the streets of New York, which disappears in one shot as the Ghostbusters fire at him. (01:30:45 - 01:32:05)
Continuity mistake: When the Stay Puft monster appears and all the cars crash, a driver goes out of a grey car through the window. In a closer angle he is back inside and repeating the movement. (01:31:15)
Continuity mistake: When Stay Puft is walking towards the church, an aerial shot shows the (miniature scale model) streets totally empty; however, a floor-level angle shows hundreds of (green screened) people who have appeared from nowhere. (01:32:05)
Continuity mistake: In the scene when they are emerging after the Stay-Puft explosion, we see Ray with marshmallow on his face and a small amount on his chest. He wipes his face, but in the shot following his apology for the burnt dog hair comment, his front side is completely covered in the stuff. (01:35:50)
Continuity mistake: In the scene when the Ghostbusters have a police escort, as they arrive at the condo building, in the wider angle of the police convoy with Ecto-1 approaching the building, the lights appear to be off, only to be on again in the next shot.
Continuity mistake: When they're all fighting in the Mayor's office, the mug on the desk changes its position between shots.
Continuity mistake: During the earthquake, after the ground swallows the police car, the crowd to the left disappears, only to appear half a second later.
Continuity mistake: Louis/Vinz Clortho is dropped at Ghostbusters office at night at the same time Venkman is drugging Dana/Zuul at her apartment. When Venkman calls from her apartment it is night, Janine is in the same grey striped blouse, black skirt and tights outfit during that call she was wearing when Louis was dropped off by the police, at this time Venkman says he is on his way back to the office. Venkman does not arrive until the next morning, during the EPA raid, he is still wearing his same brown date night jacket and blue shirt but it's daylight now and Janine has changed into a new outfit, red blouse, grey vest, grey skirt and red tights and does not look like she slept at the office, Egon has also changed at least his tie and put on a suit jacket.
Continuity mistake: When Peter gets slimed, the very marketable goo stains his uniform completely messing up the right half of his chest. In the ballroom scene the uniform is practically clean on that side, but got dirtier over the left shoulder.
Continuity mistake: When Dr. Venkman investigates Dana's refrigerator, there is a Corning dish and a can of Coke side-by-side on the top shelf. The camera cuts twice, and there is suddenly another item (looks like lunch meat) that appears in front of the Corning dish and the Coke can.
Continuity mistake: When the Ghostbusters capture the green ghost, they emerge from the ballroom. The manager then asks,"Did you see it? What is it?" and you can see he has his hands by his side, but the next shot shows him with his left hand reaching for the handkerchief in his top pocket.
Continuity mistake: When the road cracks and swallows the police car, the distance between the ambulance behind increases and decreases between shots.
Continuity mistake: Stay Puft walks behind a church, which appears or disappears depending on the angle.
Continuity mistake: When the movie is about to end, the Ghostbusters are in front of the building and the pavement starts to crack open. A group of men by the door stumble off-screen to the left. Half a second later, a close-up shows the people repeating all the previous movements.
Answer: He places it on the altar just after they believe they have vaporized Gozer with the proton packs. At this point, thinking the ghost to have been destroyed, he sets it down as he believes the job is done and he will not need it.
Jazetopher