Continuity mistake: When Dana opens the door of her refrigerator and sees the temple with a terror dog, the shelf has a bottle with a green cap and a jar with a white lid at the end of it, but when Dana slams the refrigerator after the dog says "Zuul!", both items have disappeared. (00:20:00)
Continuity mistake: After the library scene, while the three scientists are walking and talking, a woman in a striped blue and yellow sweater passes by Egon, but disappears in the immediate next angle. (00:21:35)
Continuity mistake: Egon is done testing Dana with the electrodes on her temples. He walks past her pronouncing a line; " I wouldn't rule out clarvoyance." There's a cut during the sentence, and in the first shot Dana is looking up at him, in the second she is looking at the floor. (00:23:20)
Continuity mistake: Dana is at the Ghostbusters' who just tested her with a device. When she says that she does not believe in 'those things', Ego picked up a cheez-it and brings it to his mouth. In the next shot he's not the one with a snack to his mouth, Ray is. (00:23:25)
Continuity mistake: When Peter sets foot into Dana's house, in the establishing shot of the room you can see two pink pillows on the armchair. Between their first and second appearance the pinker one in front has slumped. (00:24:15)
Continuity mistake: When Venkman is going into Dana's apartment for the first time, he plays a few notes on the piano. He does not fully open the piano key cover (just enough to play the notes). The next shot (or a few later) you can see the piano key cover completely off. (00:24:25)
Continuity mistake: At the hotel, when the Ghostbusters blast the cleaning lady's trolley, the stuff on the floor changes between shots. Watch the toilet paper on the far left, for example. (00:31:50)
Continuity mistake: When Slimer flies off after Ray shot towards him the first time, the cart rolls away; you can see that the champagne bucket was not knocked down by the messy explosion. When the cart crashes in the wall, the bucket enters the frame already lying horizontally. (00:33:10)
Continuity mistake: When the 'disgusting blob' goes through the wall above the vase of ferns after being attacked by Ray, you can see two small amounts of slime appear on the wall. In the next scene, when the food trolley crashes into the table, there is more slime on the wall than there was in the previous shot. (00:33:15)
Continuity mistake: When Venkman radios Ray to tell him about the ghost, look at the cart in the background when Ray answers; the mess does not look the way it looked in the earlier close-up; there's less stuff on the partially knocked down scaffold and the table ricocheted away from the wall but here the flowers are back on it. (00:33:20 - 00:33:45)
Continuity mistake: When the guys blast the glass lamp in the hotel, it falls on a table and messes up the table and chairs around. In the following angle the area, which was dark half a second ago is now perfectly lit. (00:35:30)
Continuity mistake: When Ray Stantz slides the trap across the ballroom to catch Slimer, the cord is curled, but it is perfectly tense in close-up. (00:37:05)
Continuity mistake: When the hotel manager refuses to pay the bill after the Ghostbusters capture the green ghost (Slimer), you can see he is putting his handkerchief into his top pocket with his left hand, but in the very next shot he can be seen putting the handkerchief in the pocket with both hands. (00:38:50)
Continuity mistake: When the hotel manager says he won't pay the 5k, the trap is facing him with the top side. As it cuts to the Ghostbusters faking to just walk back in and release their catch, the trap turned 45°. (00:38:50)
Continuity mistake: At about the middle of the film, when the Ghostbusters are rising to fame and are appearing on the front of newspapers and magazines, the photograph on the front of the New York Post is taken from the end of the film, just before the four of them cross the streams from their proton packs. (00:39:37)
Continuity mistake: When Winston gets hired, Venkman and Stantz have just come back from a job. They're covered in slime and Venkman's smoking. Ray gives Winston an armful of traps. We then cut to Venkman chatting to Dana after a rehearsal, so we assume it's later, maybe even a different day. After that scene though, we then cut back to Stantz showing Winston (wearing the same shirt) what to do with the traps, and Venkman talking to the guy from the EPA. Venkman's got the same slime pattern on his shoulder, and is still smoking. Looks like the Dana/Venkman scene was in the wrong place. (00:42:00)
Continuity mistake: When Winston gets the job after the very tough and thorough interview process, he walks up to Ray. Between shots, the messy cables of the traps Ray is holding are in a completely different position, and he holds the paper sheet at a different height. (00:42:20)
Continuity mistake: The lighting in the scene with Venkman stalking Dana outside the concert hall is inconsistent. For instance, when he quips "I've got hundreds of people dying to abuse me", Dana's stiff friend leans against a fountain that is bathed in sunlight. Mere moments later the section of the square is in the shade. (00:43:10)
Continuity mistake: At the Lincoln Center (that place Dana's orchestra plays at) the nerd with her has his case and they're leaving when Peter is there. Nerd-boy goes off to the side and waits. When they start off again, his case pops back and forth unhumanly between being carried under his arm and in his hand between long and close shots about 3 times. (00:44:34)
Continuity mistake: Venkman meets Dana by a fountain. When he says goodbye to her, first a man with a hat passes behind him and disappears in the next angle; then, in a close-up, Venkman is surrounded by dozens of people who vanish half a second later in the wide angle, where the place appears empty. (00:44:45)
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