Continuity mistake: As Dorothy and the Scarecrow dance off and sing, "We're off to see the Wizard" the flowers that were on the fencepost have been removed. The stepladder by the fence has also been moved without being touched. (00:38:55)????
Revealing mistake: After the Wicked Witch exits Munchkinland in a puff of red smoke and flames, you can briefly see sulphur marks left on the trapdoor. (00:31:00)
Continuity mistake: When the witch leans over to claim the slippers, she goes really close to them and her broom is practically touching them. Not to mention she also casts a significant shadow on the wall of the house. In the close-up of the slippers disappearing, however, the witch's broom and her shadow are not in the shot although they should be. (00:29:50)Movie_Freak 1