Continuity mistake: When Canasta is fighting Daffy in his hideout, a window by the door is smashed in the process. When Daffy opens the door and comes out with his little red wagon, he walks past the window and it is now completely intact.
Continuity mistake: When Daffy challenges Canasta to a fight, the door behind Daffy has a window next to it, but when Canasta reveals his muscles, we cut back to Daffy and the window has disappeared.
Continuity mistake: When Porky tells Daffy to arrest Nasty Canasta, you can see the window next the door has four panes of glass, but when Daffy challenges Canasta to a fight, the number of panes has increased.