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: 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)
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)
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: 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: In the forest scene when they walk up to the warning sign, watch and you'll see the Scarecrow's stick bend like rubber.
