Continuity mistake: When the four are at the end of the hallway to see the Wizard, Toto is near the lion's feet. As it switches shots, he is behind The Tin Man.
Other mistake: As they walk through the forest in the shot before Dorothy says, "I don't like this forest" there are some cool digital glitches in the lower left hand corner of the screen which look like a strand of blue Christmas lights blinking on and off. (Restored and re-mastered DVD version only). (00:48:00)????
Visible crew/equipment: Near the very beginning, when Dorothy is with Prof. Marvel, after she runs out of his trailer and the wind starts blowing, he follows her and goes towards his horse tied up outside. As he's walking towards the horse, you can see the shadow of a boom mic along his trailer. (00:14:55)