Continuity mistake: When Sylvester is trying to sleep in his bed at night, you can see next to him there is a dressing table and on it there is an alarm clock and a hairbrush. Watch the hairbrush: in some shots it is next to the clock; others it isn't.
Continuity mistake: When Sylvester sees the Daily Bugle newspaper, the front cover headline reads "Police Hunt The Cat." You can see the words THE CAT have nothing around them, but when we see a close-up of the newspaper in the next shot, inverted commas have suddenly appeared.