Continuity mistake: Fred falls into the secret passageway while carrying a lantern with him. In a few later shots of him on the ground, the lantern is gone.
Continuity mistake: When the gang first drives up to the house, there are no cats on the front porch. Then a few seconds later, as Fred points out, "this place is crawling with cats".
Continuity mistake: The boss enter the storage room carrying the clipboard in his left hand. In the next shot, when Shaggy says "Like, hi boss" it's in his right hand.
Continuity mistake: Velma adds books to the pile in front of her when she takes the telephone order. Looking down the pile, you don't see any trace of the random loose papers that appear when she hauls the whole lot to the desk with the TV on. (00:06:25)
