Continuity mistake: When Prof. Marvel holds the photograph, his fingers disappear in the close-up.
Continuity mistake: As the Professor is revealed behind the curtain, his right hand is busily working one of the silver levers. A second later, it's working one of the red levers above the big dial.
Continuity mistake: When the Tin Man is levitated and falls to the ground the metal covering his left leg is crumpled up. When we see him again from behind as the flying monkeys attack, the metal covering his leg has never been bent. The metal on his lower back has also been repaired since the fall. (01:14:05 - 01:15:05)
Continuity mistake: If you look at the cracks in the floor, the Wicked Witch's cape moves between shots after she is "melted". (01:26:45)
Continuity mistake: In the haunted forest when the Tin Man is levitated then dropped, the tin surrounding his upper left leg gets bent on impact. Later in the movie, the tin is perfectly formed and unbent.
Continuity mistake: When the Witch turns the hourglass, the spoon in the mortar behind her moves around between shots.
Continuity mistake: Toto runs away from the castle and Dorothy starts to cry. The angle changes and her left arm is now raised and she is also not crying as bitterly as in the previous frame.
Continuity mistake: Dorothy arrives at Prof. Marvel's cart and stands very close to the sign on the side. When the angle changes, she is standing several meters behind.
Continuity mistake: When the Witch flies off to Emerald City the monkey is standing by the window sill. The outside angle, where the window and rest of the set are a matte painting, has the Witch superimposed, but not the monkey.
Continuity mistake: Dorothy's house is outside of the tornado when we first see it up in the air. Then they are immediately inside the tornado. (00:17:15)
Continuity mistake: When the Wicked Witch tells Nikko "throw that basket in the river and drown him" his feet can be seen resting near her book of spells. In the next shot we see the book of spells back where it originally was to the right of the lamp. (01:16:40)
Audio problem: When Dorothy first meets the Scarecrow, you hear Scarecrow talk about the directions, but his mouth doesn't move.
Revealing mistake: When the Wicked Witch leaves to go to Emerald City on her broomstick, just before she rounds the tower, a couple of thin wires holding her up are visible.
Continuity mistake: When the Wizard is in the balloon, he raises his top hat pointing in an 11 o'clock direction. A frame later it's pointing in a 9 o'clock direction.
Continuity mistake: Talking to the Wizard the Scarecrow says, "What about the heart you promised Tin Man " and the position of the characters changes between shots. (01:29:15)
Revealing mistake: Right after Dorothy slaps the lion, there is a green smudge on her arm. Looks like the witch's makeup. (00:50:35)
Suggested correction: There is no "green smudge" on her arm. Perhaps this is referring to the blue mark that appears on her arm as she talks to the lion? Because I'm not seeing anything on her arm that is green.
Continuity mistake: At the start of the film when Dorothy comes running into the farm calling Aunt Em, Uncle Henry has just taken a chick out of a hat, and is placing it into an open coop. Yet when the shot changes his hand is instantly back in the hat taking out another chick. (00:02:15)
Continuity mistake: In the scene where Dorothy and the Scarecrow first meet and oil the Tin Man, the leaves on the Tin Man's shoulders appear and disappear several times. (00:40:50)
Continuity mistake: When Dorothy and the Scarecrow find the Tin Man and oil his mouth, between shots, the leaves on the Tin Man's shoulders change.
Revealing mistake: When the doorman initially refuses to let Dorothy and friends into the Emerald City, they protest, saying the Good Witch of the North sent her; they show him the ruby slippers as proof. As the camera pans down to the slippers, look at the yellow brick road Dorothy is standing on - it is flat and looks as though it was simply painted.