When the Professor says, "Time for bed, girls", Buttercup's mouth disappears.
Bubbles's mouth does not move for the first time she says "Duh" when she and her sisters explain to Ima Goodelady that it's their job to fight crime.
The band Bis that performs the show's ending credits theme, while the lyrics state the Powerpuff Girls are "trying to save the world" while fighting crime, they are actually saving the city of Townsville that is one city on the planet that is the main setting of the series that's under attack as no other known cities in the series are shown to be under attack.