Continuity mistake: When Mark is editing his film at the end of the movie, there is a segment of Angel when he was singing "Today 4 U," Mark never filmed during that scene. At no point during Angel's performance does Mark pick up his camera and film Angel. We see Mark without his camera just watching Angel. (00:26:50 - 01:54:55)
Continuity mistake: When Max Bialystock is singing "Along came Bialy", and the old ladies start coming out of the apartments, the first lady who comes out isn't there in the next shot.
Continuity mistake: When Dorthy runs back into the trailer to get her pet the windows break and are all messed up. But look at the window that breaks in one shot it is perfectly fine next messed up. It changes many times thought the whole scene.