Revealing mistake: The Thing takes a swing at the captain after the captain opens the door. As the Thing swings his arm, he takes out a chunk of wood out of the door. If you step through the frames on the DVD, you can see the wood leaving the door a full second after the Thing has hit it. A small explosive charge that was not in sync with the actor. You can also see the outline of where the wood comes off before he swings his arm. And one more thing, his arm does not touch the door or even comes close to where the wood comes off - a safety precaution I presume. (00:57:33)
Visible crew/equipment: When the airplane flies over the area where the saucer skidded in and became buried in the ice, you can see the equipment used to clear the snow and smooth out the ice (at the narrow end of the ice). You can also see the tracks from the machine criss-crossing the circular portion from the aerial shots. (00:16:20)
Other mistake: When the captain comes face-to-face with the Thing for the first time, the upper right frame becomes blurred once the door starts opening until it closes followed by a scene change. Very odd except maybe they were trying to hide the minicharges to create the bullet holes after they close the door. The implanted charges are very visible when the scene is not blurred. Also there is a small charge in the wooden frame of the door near the door handle. (00:57:32)
Audio problem: While at the saucer crash site, some of the characters approach the air foil of the saucer. Dr. Carrington asks Vorhees if he can tell what metal it is. After Barnes is asked to bring some tools, watch Dr. Carrington's lips. He's obviously talking to Captain Hendry, but there is no audio.
Factual error: The scientists are supposed to be at or near the North Pole. When Capt. Hendry takes off from Anchorage, Alaska the sky is dark (day-for-night) but when he arrives at the Polar base it is broad daylight. The dialogue says the date is Nov. 2 (presumably 1951). Later, when the "Martian" is accidentally released from his block of ice by an electric blanket, the sky is dark again. Later the sun is back up. At the North Pole the sun sets around Sept. 21 and stays down until March 21, when it comes back up. NOAA says polar twilight lingers through "early October" but by November the sky is black 24 hours a day and stays like that for most of the next six months. Also, when he arrives Capt. Hendry is told the explosion took place about 50 miles "due East." If you're at the North Pole there's no such direction as "due East". No matter which way you head, you're heading due South. And from the plane, Hendry refers to "that peak ahead" being due East. The Arctic ice cap is a thick sheet of ice floating in the ocean. That's why submarines can sail underneath it. There are no "peaks" near the North Pole. These guys were thinking of Alaska, not the North Pole.
Audio problem: After arriving at the saucer crash site, a few members of the expedition approach the air foil of the saucer. Dr. Carrington asks Vorhees if he can tell what metal it is made of. After Barnes is asked to bring some tools in order to take some metal filings of the air foil, Dr. Carrington is obviously talking to Captain Hendry, but there is no audio. Mistake observed in video format.
Continuity mistake: In the early scene in the officers' club, the money in the center of the poker table disappears and reappears with the change of angle.
Audio problem: After the captain checks the x-ray room for the Thing, he turns off the light. However, we hear the click after the light starts to turn off.
Revealing mistake: The search team uses thermite charges to melt the ice around the saucer. After the initial explosion, the ground begins to rumble and the members of the search team all dive to the ground as the space ship itself goes up in a tremendous blast. Look at the sled dogs when the scene cuts from the explosion to the team huddling on the ground. They stand there calmly observing the scenery - no barks or yelps even though a violent explosion has supposedly rent the ground about 100 feet away from them.
Continuity mistake: In the inside shots of the airplane, gear is piled up in front of the windows. In the outside shots, you can see clear through the cabin to the windows on the other side of the plane, with no gear or passengers anywhere to be seen.
Visible crew/equipment: When the scientist finds the saucer near the North Pole, the panorama of the sky reaches only to a certain height. When the camera pans upward, as the smoke billows up from the explosive charges, the backdrop of the sky disappears and the real sky appears above the Hollywood backlot. (00:22:55)
Continuity mistake: The first time they confronted the thing at the greenhouse door it opened outwards, which is why they brace the door from opening. But later in the movie right before the end, that same door opens inwards.
Factual error: The Thing is in a block that would weigh a good 2 tons, how did they get it on the plane? Would the plane even take off with that type of weight? and the block of ice with the Thing in it seems to be up on a table of saw horses, neither of which could take that type of weight.
Factual error: When the doctor is showing his colleagues where the seedpods are growing, a fly lands on Dr. Karagen’s eyebrow for a split second. What is a fly doing in a subzero climate?
Visible crew/equipment: When Bob approaches the door to the greenhouse with a geiger counter, the wire to the device can be seen trailing out the bottom of his pants leg on onto the floor.