Continuity mistake: In India, Claude asks the Guru where the sounds came from, while a huge crowd walks along the desert. When a man in blue addresses the crowd to ask them, the crowd on the right side is gone, and the ones on the left aren't walking but standing perfectly formed like an army.
Continuity mistake: When Ray first arrives at Devil's Tower and stops the station wagon, the broken fence post resting on the hood changes positions between shots. In the view of him through the wind shield, the post is lying straight, parallel to the length of the wagon. In the next shot, it is suddenly at an angle, even though the car hasn't moved. (01:21:30)
Audio problem: In the scene just as Roy, Gillian, and Larry take off for Devil's Tower, the army officer is on his car phone speaking to his superior. When his superior tells him if they don't get Roy and company off the mountain in one hour, to use EZ4. Lacombe, who was talking to David at the time, looks at the officer and says, "What's EZ4?". Lacombe should not have known what was said over the phone, as only the officer and we, the audience, knew what was being said. It wasn't a speaker-phone. [The army officer was using a VRC(vehicle radio console.) Not a cellular phone. The radio has a speaker mounted on the front of the console in addition to the speaker in the handset. So everyone would be able to hear the conversation on the radio. ].
Continuity mistake: When Roy says to Ronnie, "I saw something last night that I can't explain.," and he bridges his arms across the door frame his forearms are parallel to the ground. In the following shot, when Ronnie straightens up, Roy's forearm points upward. (00:36:15)
Character mistake: "Cosmic Kidnapping" is spelled incorrectly with a missing P in a newspaper article at the press conference where he breaks his pencil while drawing.
Continuity mistake: After Roy fills their kitchen with shrubs, bricks, soil, and chicken wire, Ronnie takes their three kids out of the house and into their station wagon. She tells her kids to lock the doors, but the driver's side door lock is up (unlocked). When Roy walks around the driver's side to speak with Ronnie, the driver's side door lock is now down (locked). (01:10:05)
Continuity mistake: Barry is leaving his house, going towards the trees. Jillian looks out her upstairs window and Barry as well as the immediate area surrounding him are drenched in bright direct light, as if from a spotlight mounted on the side of the house. However, from an outside angle of the scene he is not bathed in light, and neither is the area he is in.
Continuity mistake: When Barry is taken from the house, just before that happens we see a grate get blown out of the floor and it lands on its side. In the next scene the grate is back in the hole, but at an impossible angle, even if it fell in.
Continuity mistake: When Richard Dreyfuss is building the model of the Devil's Tower in his living room, behind him in the sliding glass doors you can see that it is raining, and when he turns around and walks to the door to look out, it is now sunny, and people are out side mowing the grass and children playing. (01:15:40)