Continuity mistake: During the tornado scene while she's in her bedroom, there is a small oval picture (which looks like Elvira Gulch) over the bed which ends up sideways. As she gets up to leave after the house lands, it's straight up. (00:19:15)
Visible crew/equipment: The four run away from the guards and leave the tower where the Wicked Witch is eventually melted. If you look closely in the two long shots from above them, the Tin Man reflects the bright stage light that is placed below them at the first bend of the walkway, on top of the Witch's castle. (01:25:25)????