Continuity mistake: When the Gophers hear Elmer Fudd and the furniture salesman coming, they hide in the bottom drawer, but when Elmer drives home, the Gophers are now hiding in the second drawer down.
Continuity mistake: When Daffy Duck pursues the stork with an axe, you can see the doors of the alligators' basement are closed. But when Daffy falls into the basement after cutting the telegraph wire, one of the doors is now open.
Continuity mistake: Before Tom is about to draw a line on the alarm clock on the blueprint, you can see on the left hand side of the clock there is an "A" and an arrow, and on the right hand side is some writing. When Tom draws the line, the "A", arrow and writing have all disappeared.
Continuity mistake: When Jervis returns Julie to her suite after a night of dancing, he picks up a morning paper, reads some excerpts from it, then says goodnight to her. As she opens the door, all he has in his hands is his boater, no newspaper, and in the following long shot, no paper is visible anywhere.