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)
Revealing mistake: When the guys are looking down at Stay Puft, as he is about to crush the church, Stay Puft approaches Dana's apartment and you can see a support structure to the right of Stay Puft's right leg. (01:32:00)
Revealing mistake: When the Stay-Puft Marshmallow Man is walking through the city, in several shots you can see outlines of people and buildings through the marshmallow man, who was added in optically. (01:32:05)
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)
Revealing mistake: Near the end of the film when the Ghostbusters take cover in a small corner and come up with the "cross the streams" plan, look closely at Peter's proton pack, you can see that it is a foam "stunt" pack as there is a small sticking out part that keeps squashing against the wall behind him. (01:32:25)
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)
Factual error: At the very end of the movie, Ray is telling Louis about the Tunguska Blast of 1909, but the famous blast actually occurred in 1908. Given his oft-demonstrated levels of knowledge, he'd know better. (01:37:38)
Other mistake: Winston Zeddemore's surname is spelled as "Zeddmore" in the closing credits. (01:43:50)
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.
Revealing mistake: In almost all the aerial shots of Dana's apartment block, the traffic on the ground is stationary (NB - this is explained in the SFX documentary on the Special Edition DVD/video - matte paintings were used for those shots)
Continuity mistake: When they're all fighting in the Mayor's office, the mug on the desk changes its position between shots.
Revealing mistake: As Dana's apartment crumbles apart to present the temple of Gozer, there is a tight shot of a gargoyle falling off an exterior corner. Carefully lined up with features on the gargoyle's face - but still readily visible - are the black strings that pull the gargoyle face off its mount.
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.
Factual error: When the Archbishop arrives, Lenny greets him with "Your Eminence," which is a greeting for Cardinals. However, the Archbishop is wearing purple, while a Cardinal would wear red, indicating he was not a Cardinal. New York usually has a Cardinal for an Archbishop, anyway, and the production team likely just assumed the greeting without knowing the color rules. The correct greeting for an Archbishop would be "Your Excellency." In this case, either the greeting or the wardrobe was wrong.
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.
