When they're 'jogging' around the dance floor, Gloria's shirt is soaked with sweat. In the next shot it has only one sweat spot, and in the next it's all drenched again.
When Sailor (Red Buttons) is passed out, two referees take his pants off him to dunk him into a tub of ice water; Buttons lifts up his hips so they can easily remove his pants.
The film is supposed to take place in 1932. However, during the opening sequence posters for the films Varsity Show (1937) and Off the Record (1939) can be seen outside the ballroom on the pier.
Robert tells Gloria about a film he saw starring Anita Louise and Richard Cromwell in which Anita Louise's character has a brain tumor. However, Louise and Cromwell only made two films together, Most Precious Thing in Life (1934) and The Villain Still Pursued Her (1940), both of which were made after 1932. The plot described does not resemble either of these movies but is very similar to that of Dark Victory (1939), which was also made after 1932.
When Gloria's partner is rejected from participating in the marathon for being sick, she points to Ruby and snaps, "If she ain't pregnant, I'm Nelson Eddy." In 1932 Eddy was not yet a well-known figure in show business.
At one point when Joel and Alice are in the spotlight, the band plays the song "You Oughta Be In Pictures", which wasn't composed until 1934.
The Edward Heyman/Johnny Green (as John Green) song "Easy Come, Easy Go", which is used as the film's title theme and is performed by a singer at the fictional dance marathon, was not published until 1934 (two years after the film's 1932 setting).
Shadow of camera and operator on Derby contestants.