When Velma pushes the button for the cage it is a small button but in the next shot it is a big one.
When Fred's shown wearing his wrestling costume for the first time from front view, the cape's color is white judging from the cape's attachment on his shoulder. However, when he's lifted by "Scientist", it's shown that the color is blue. Furthermore, the color of the cape's attachment is different in one occasion.
The aquarium's sign changed from "Do not tap on the glass" into "do not touch glass" when Shaggy and Scooby tried to hide from the Titanic Twist.