Other: In the scene where Walther Matthau is making sandwiches for his poker pals (during the movie's first poker game), Matthau drops a loaf of bread on the kitchen floor. If you look at his hand, you'll see that he flicks his thumb to make the loaf of bread fall.

Continuity: In the opening sequence, Felix (Jack Lemmon) goes into the Metropole Cafe. One of the people he passes as he enters is a young woman with a thin face and very distinctive nose and eyes. He goes in, has a drink, hurts his neck, and leaves. As he is leaving, the camera pans the band and go-go dancers. One of the dancers is the young woman who had just left as he was entering.

Continuity: When Felix enters the Flanders Hotel at the beginning and asks for a higher room, the man behind the counter puts his pizza on the counter, but in the next shot, it's in his hand again.

Plot hole: During the first poker game of the film, Vinny (John Fiedler) picks up one of his poker hands and straightens the cards in such a way that everyone else at the table can see them. Since the other guys gripe about how much Vinny is winning, neither Fiedler nor director Gene Saks must've known that his cards were visible.