Revealing mistake: When Louis gives Gage the lethal injection, because the syringe is transparent you can actually see the prop needle retract in and out of the syringe as he supposedly injects Gage.
Continuity mistake: When Carlotta brings the plates for the meal they all have a dome cover with a top handle, but when Sebastian runs across the table those handles have changed. (00:54:50)
Factual error: Joe Jackson batted left-handed in real life, not right-handed as Ray Liotta portrayed. He also threw right-handed and not left-handed like it shows when Kevin Costner is hitting him fly balls to left field.
Continuity mistake: When Philip surprises Alex and Corrine undressing in the living room, Corrine throws her panties in the air and they land on Philips' head. Philip pulls the panties off his head and throws them down. After a quick cut to the surprised Alex and Corrine, the camera cuts back to Phillip with the panties magically back on his head.
Revealing mistake: When Nick is being sucked out of the hole/cave, you can see the wires visible from his waist. (01:20:35)
Revealing mistake: In one shot when Alice is in the shower, as she turns for the soap you can tell she is wearing brown underwear. (00:03:30)
Continuity mistake: When Vigo throws the streams from the proton packs back onto the Ghostbusters, there is a wide shot of Egon getting thrown way over to the right. However, when they do a closer shot, he is way over to the left, closer to the other three Ghostbusters. (01:33:50)
Continuity mistake: During the last scene, right before Louise takes off her necklace, Brad is seen dancing with his jacket on. Seconds later when we see him again he has his coat off and now he's on the side of the dance floor.
Revealing mistake: During the Hy Brasil sinking sequence you can see a horizontal line in the water in the background, this is the edge of the water tank they used to film this sequence. It's also visible in several shots from the longship.
Continuity mistake: When Dorinda comes to see Pete off the last time she throws her bike on the runway. When it falls down the front wheel turns so that it almost points backwards, but when she picks it up later it points ahead. (00:31:30)
Continuity mistake: When Brian spends his first night in the underground monster world he goes in wearing a shirt and boxer shorts. But a later scene shows him wearing a shirt, pants, and shoes. He then goes back home and is back in his shirt and boxer shorts.
Suggested correction: It's entirely possible that he was able to borrow a pair of pants while down there.
I just watched the scene where Maurice and Brian pull the pranks to get the kids into trouble and he is in his pyjamas. Later in the monster world he is in a full outfit including a shirt, pants, and shoes. Then he goes back home and he is in his pyjamas again.
Continuity mistake: Barbara Carrera's Priscilla has shoulder long hair most of the time yet at one point she's sporting a ponytail that reaches her waist.
Revealing mistake: In the scene at the graveyard, after the Warlock assembles the Grand Grimoire and commands it to say God's true name, the fake headstone behind him starts to fall over. (01:33:02)
Suggested correction: Other headstones can be seen falling before this scene.