When Sam walks down the street, she takes several large bites of her ice cream cone. Not only does the ice cream regenerate, it changes flavor several times.
In Sam's apartment, Jack's bottle of Dr. Pepper turns into a can
in the next room.
At the beginning of the "You Can't Stop the Music" song finale, the Village People are shown from the front. The cop is on the far left, next to the cowboy. In the very next shot, as they're being shown from the back, the cop is between the Indian and the Biker.
While the friends talk in the street, before the YMCA song, the Indian appears behind Samantha, then walks behind the cowboy. He appears again behind Samantha before they keep walking.
At least one camera man is visible in the audience during the concert at the climax.
When Sam is at home with Jack and the Indian, she walks holding a spray bottle up to a plant. While she walks the shadow of the boom mic appears on the top of the wall.