Revealing mistake: When the boat is supposedly surrounded by a swarm of flies, they're really just relatively few flies trapped between two panes of glass in front of the camera lens. Evidence: whenever the camera moves, the "swarm" moves with it against the background, and you can even see some of the insects walking on the surface of the glass.
Revealing mistake: When the torpedo is fired at a Japanese ship, the underwater shot of the torpedo cruising reveals it being pulled by a long wire. It is also apparent that it was filmed in a tank with the reflection of the sun on the tank wall.
Revealing mistake: The man from Mars is in an elevator with a woman when the power goes out. He tells her he cut the electricity and gas powered engines all over the world for a half an hour. They proceed to show clips of the power out in different parts of the world. When they get to Big Ben in London, you can see a motorboat cruising down the river in the background. If the boat were powered by wood or coal, there would be plume of smoke trailing it. If it were powered by oil (ie. diesel) electricity is required to pump the fuel into the ejectors. (01:02:05)
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)
Suggested correction: It is not a full second delay. It is four frames which translates to 1/6 of a second. Everything described in this entry is only visible if you step through frame by frame which invalidates the mistake.
Revealing mistake: After the Indians have attacked the wagon train Robert Taylor returns to see the devastation. When they call out the names of the dead we see a close up of each person and some of the "dead" are breathing.
Revealing mistake: Early in Act I, Kate Reid puts a glass in the sink (below our sight line) and turns on the faucet. No water comes out, but she reaches down and produces a full glass of water.
Revealing mistake: When the Christians are being fed to the lions, we can see that when a lion "attacks" one of the men, the man is actually smiling and visibly playing with that wild animal.
Revealing mistake: When The Indians launch their final attack (towards the end of the film), on a old outpost held by a small group of soldiers, Ward Bond is hit by a arrow which enters the right side of his chest. In the next shot you see Gregory Peck removing the arrow from the left side of Ward Bond's chest.
Revealing mistake: When Captain Quincy Wyatt interrogates a captive Seminole Native American by threatening him with a poisonous snake, the native is safe because there is a protective piece of glass between him and the snake. The snake's reflection is quite obvious on the glass panel. (01:14:40)
Revealing mistake: During the first shot of the rocket ship coasting through space stars can be seen through it.
Revealing mistake: When Alice tells the Mad Hatter how she appeared in Wonderland the hare's paw is superimposed on the teapot's handle as if the pot were flat or he was floating.
Revealing mistake: When Lou and Tommy are in the car at the park, and Tommy is taking the disguise bandage off his head, a very faint outline of Tommy's head is visible under the incomplete special effect.