Continuity mistake: While Peggy's singing "42nd Street" for the show's premiere, she suddenly goes from tap-dancing on stage to being on top of a car's roof right in the middle of her performance. (01:24:01)
Character mistake: During the music number "Shuffle Off To Buffalo", two females are singing about the main couple while eating. The character on the right starts singing about the male having a shotgun to his "belly." She is supposed to say "tummy" and quickly corrects herself.
Suggested correction: Per Wikipedia, this error was intentional. "there is a single moment at the end of "Shuffle Off to Buffalo", when one word of the scripted lyrics, "belly", was changed to "tummy" presumedly to comply with the then weakly enforced Motion Picture Production Code of 1930. But in making the change, the filmmakers purposely drew attention to the censored word. As Ginger sings it, Una gestures to her and she changes the last word: "He did right by little Nellie, with a shotgun in his bel - - tummy.
Visible crew/equipment: During "Shuffle Off to Buffalo" the camera tracks backwards as the set of a train opens. The track the camera is sitting on is blatantly obvious on the bottom of the screen.
Suggested correction: This brilliant shot is not photographed by a camera on a track but on an overhead crane (in order to clear the orchestra pit) so there are no tracks visible.
Character mistake: On the marquee at the Philadelphia theater where the musical "Pretty Lady" will be performed, lights spell out GALA PREMIER. A premier is the ruler of a country. The debut of a musical is a première.
Suggested correction: "Premier" as an adjective means "earliest creation", such as a primer issue or "first in importance or order." In fact, in 1933 "Mickey's Gala Premier" was released. Only as a noun does it mean prime minister or other head of government.