Continuity mistake: When singing 'Ding Dong the Witch is Dead', in a wide shot, many Munchkins run up to Dorothy, in a big crowd right beside her. But in the next wide shot when the mayor is saying 'From now on you'll be history' the crowd has gone. (00:27:20)
Continuity mistake: The blue Lollipop Guilder scoots up to Dorothy with his hands in his pockets. In the next shot his thumbs are sticking out. (00:28:05)
Continuity mistake: Dorothy faces the Munchkins as they sing, "We welcome you to Munchkinland". In the next shot she's facing the Mayor. (00:28:30)
Audio problem: At the very end of, "We Welcome You to Munchkin Land," at the very last 'fa la la la la laaaaaa' right before the Wicked Witch interrupts the song with her explosive arrival, you can hear someone scream before the explosion even occurs. (00:29:04)
Continuity mistake: The length of the bristles in the Witch's broom changes throughout the movie. (00:29:15 - 01:26:10)
Continuity mistake: In the scene where Dorothy is confronted by the wicked witch and the lollipop disappears from her hands, notice how the flowers keep moving positions in her hands. (00:29:30)
Visible crew/equipment: In Munchkinland as the Wicked Witch of the West walks over to her sister the shadow of the cameraman can be seen going across the Wicked Witch of The East's shoes from left to right. (00:29:40)
Continuity mistake: As the Wicked Witch walks over to her sister a rocking chair is protruding through the broken window. In the next shot the window frame disappears and it's not a rocking chair anymore that's protruding from the window. (00:29:45)
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)
Revealing mistake: In the scene when the Wicked Witch of the West bends down to retrieve the ruby shoes from the feet of her sister sticking out underneath Dorothy's house, there is one quick shot in the middle of the scene that shows her in front of a screen with a picture (film) of the house on it. Maybe that shot was filmed after the original set was unavailable? That would seem to be the only possible and reasonable explanation why such a shot would be necessary. (00:29:55)
Continuity mistake: Glinda tells Dorothy, "Their magic must be very powerfulÂ…" and Dorothy has her left hand around Toto. In the next shot she's holding the flowers in front of her. (00:30:20)
Continuity mistake: Just before the Wicked Witch leaves Munchkinland she says to Dorothy, "just try to stay out of my way" and her broomstick is facing upwards. In the next shot it's facing downwards. (00:30:35)
Revealing mistake: When the Wicked Witch scares the Munchkins in Munchkinland, where Dorothy lands, she disappears into a cloud of smoke she creates. But you can see her sneak down into a trap door below. [As a sidenote to this entry, Margaret Hamilton was hospitalized for severe burns after a take of this shot (not the final one used) when the stage elevator got stuck and the explosion went off.] (00:30:45)
Continuity mistake: After the Wicked Witch leaves Munchkinland Dorothy is standing in front of Glinda one step below the top. In the next shot from behind she's two steps below Glinda. (00:30:55)
Continuity mistake: Glinda says to Dorothy, "I'm afraid you've made a rather a bad enemy of the Wicked Witch of the WestÂ…" and the mayor of the Munchkin city walks up from behind them. In the next shot he re-approaches them from the left. (00:31:00)
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)
Visible crew/equipment: Glinda sends Dorothy off saying, "Just follow the Yellow Brick Road" and Dorothy walks through the shadow of the camera's crane. (00:32:05)
Continuity mistake: The Lollipop Guild teleports all over the scene. As Glinda departs, they are behind Dorothy. As Glinda's bubble rises, several Munchkins run to where she was and wave goodbye, green shirted Lollipop Guilder (Jerry Maren) among them. Cut to Dorothy and Jerry's still behind her. (00:32:40)
Continuity mistake: Before Dorothy leaves Munchkinland she has a blue flower in her basket. She never touches the basket but as she dances out of town it's not there. (00:32:55)
Continuity mistake: When Dorothy first meets the scarecrow, there is a patch of grass in front of the field the scarecrow is in. On the grass there's two beds of flowers. The flowers change colors from when Dorothy meets the Scarecrow, to when the Scarecrow starts his "If only I had a Brain" song. (00:33:00 - 00:35:30)
Answer: In the film it's left ambiguous. At the end it's strongly implied that she was dreaming. The characters she meets all look like people she actually knows. In the original book, she actually went to Oz.