Revealing mistake: When Rob is in the Cafeteria eating all the coleslaw, he yells "I'm the coleslaw king of the world!" there is a girl in the background who mouths it as he is saying it. (00:50:00)
Revealing mistake: In the library scene when Richie sees Pennywise the clown, all the balloons filled with blood are popping on people who aren't supposed to be able to see them, but one lands on a lady and you can see her jump as the balloon pops.
Revealing mistake: When the kids step out of the water and walk towards the house, the floor is already soaking wet from previous takes.
Revealing mistake: When Jack and Rose are running from the raging water that is gushing down the hall after them you can see the faces of the stunt doubles through the computer generated ones of Leonardo and Kate (slow motion can help but isn't essential). (02:17:15)
Revealing mistake: Near the end of the movie, when Maverick's plane is about to be launched, there is a quick closeup of an F14's nose gear, which is quite obviously not hooked up to a catapult or anything else.
Revealing mistake: When you see the first shot of the dead Mercutio, he's still breathing.
Revealing mistake: A horse gallops through a field and you can see a telephone pole.
Revealing mistake: It is not what is seen here that is the problem, but what we don't see on the Hogwarts Express; first on the way to Hogwarts when Harry, Ron, and Hermione are in their compartment talking about Draco, and second, during holiday break, when Harry and Ron are talking about Unbreakable Vows. As the camera faces the large compartment window, we see the scenery out the window, but as the train speeds along, the scenic reflection of the windows opposite it, in the corridor, should be seen but isn't. What is reflected is the light colored wall of the compartment beneath the blacked-out window. The camera filming the shots from this angle is positioned at that window, and to hide the camera/crews' outline, the window was covered.
Revealing mistake: The road leading out of the samurai village has distinct tire tracks from vehicles.
Revealing mistake: Candace's eyes are moving and she is breathing after allegedly having been shot and killed.
Revealing mistake: Mrs. Doubtfire sets herself on fire. When she jumps back and starts fighting the flames, it is obviously a stunt double as her face is longer.
Suggested correction: If you look carefully, the face looks pretty much the same, as well as the voice.
The reason the voice was the same is that it was probably an audio dub, which is a voice recording over someone else's voice.
Revealing mistake: When the final race is under way, the silver Saleen S7 hits a Police SUV and makes it flip, you can see the smoke coming out of the bottom of the SUV where the cannon has fired to flip the SUV.
Revealing mistake: In the scene where Themistocles first talks to Queen Gorgo, in the background you can see several extras, one of which is wearing obvious sneakers. (00:18:35)
Revealing mistake: When Tommy Ross gets killed and Carrie looks at his supposedly lifeless body if you look closely you will notice he blinks revealing that he is actually alive.
Revealing mistake: After Jim's horse is shot from under him while running down the really steep hill, and Jim later regains consciousness, before he turns and finds his horse dead, if you watch closely you can see the horse still breathing.
Revealing mistake: Just before Marguerite tastes the chocolate Henry gives her, in the shot of the group walking past a pen of geese, the modern, flat, white soled shoes (likely canvas sneakers) the sisters are wearing are visible as they walk. (00:51:00)
Revealing mistake: In the final Indian chase at the conclusion of the film, when a covered wagon rolls over, one can see the rope that was used to ensure it tipped over.
Revealing mistake: In the first scene at the beach, where Ali carries Stephanie to the water, you can see the shadow of her legs, despite her legs being amputated. (00:41:25)
Suggested correction: Can you? You can see his shadow for sure, but I don't see her shadow cast on anything. I was looking for this mistake on Prime - I added the timecode for the scene too (41:25) in case someone wants to check out and maybe submit a screenshot, too - but I personally can't see it.
Revealing mistake: When the taxi goes over the edge to capture Dr. Neville, you can see that the underbody of the car as it goes over is a flat painted surface and not the underside of what should be there (i.e., muffler, gas tank, etc.).
Revealing mistake: When Wade gets shot, watch the shot where Upham brings the bags up to the injured medic. The next shot there is some fog which then reveals the injured medic. In this shot, watch carefully as the cast rips away the medic's shirt. If you look near the neck, you can see the fake stomach vest he is wearing for a split second - when the actor realises he ripped too far up, he quickly covers it back up. (01:28:43)