1) When Dorothy is in the cyclone, the paper laying on the desk near the window does not move, but the picture on the wall does.
2) When the Wicked Witch of the West disappears from Munchkinland in a cloud of smoke and fire, the smoke appears before she reaches her mark.
3) After the Tin Man is dropped by the "spooks", Dorothy and the Scarecrow run up to him. As he attempts to get up the top of the costume comes up, and you can see Jack Haley's t-shirt.
4) After the Scarecrow, the Tinman and the Lion rescue Dorothy, they run downstairs. As the door slams shut, the order is Scarecrow, Dorothy, Tinman, and Cowardly Lion. In the next shot, Dorothy and Tinman have switched positions.
5) A square block of wood to which the Lion's tail was attached is visible when the Tinman is pulling on it while climbing up a hill.
6) When the Wicked Witch of the West throws fire at the Scarecrow, the fire goes out just as the Tin Man begins to use his funnel to put it out.
7) When the house finally lands, the furniture and floors are level, indicating that it landed flat and intact. Yet when we see the exterior after Dorothy has entered Munchkinland, the right end of the house's foundation has nearly broken in half over The Wicked Witch of the East, and the siding has sustained major damage.
8) When Toto reveals the Wizard by pulling the curtain aside, he doesn't use his mouth; the curtain is tied to the dog. Dorothy can even be seen later removing the rope.
9) In the "King of the Forest" scene, Dorothy trips up the emerald carpet on her way back up the stairs.
10) The lion's crown, which was made from a shattered flower pot, bounced on the floor when knocked off by the guard, and When it was made, without breaking.
11) When Dorothy is helping to oil the Tin Man, she grabs onto his arm and shows that the "tin" arm is quite flexible.
12) When Dorothy meets the Scarecrow, the string that is holding him up is visible.
13) As the Lion is singing, "If I Were the King of the Forest," and his tail is flopping from side to side, a string cam be seen controlling his tail. Just before the Scarecrow and Tinman put on the Lion's cape, you can see the Tinman remove the wire with a quick yank.