When Albert and Marie arrive at the Science Academy Awards - Einstein say that he's taking the hot air balloon down - and then proceeds to pull the cord to turn on the burners - which should take the balloon up - instead it goes down.
Albert's "guitar" only has four strings. That's because it's made from a violin. He is inventing the guitar by modifying a violin.
When Marie talks to Albert in the Lunatic Asylum's shower room, "If you won't do anything, who will?" is dubbed over "If you won't do anything, I will."