Revealing mistake: When three of the turtles are playing trivial pursuit and the fourth runs in to announce Splinter is alive, you can see a wire coming out of Raphael's shell. I guess it's for the animatronic head but it's clearly visible.
Revealing mistake: As Michelangelo is waiting for the pizza guy, Donatelo cames through the sewer on a skateboard. A view of his feet is shown and his hands swipe across the screen. One of the times they come through his hand is not that of a turtle, but a human hand.