Continuity mistake: Fluttershy's neck disappears after she says, "I don't know if I can cheer enough to help her".
Continuity mistake: When Sylvester enters his mother's house, he slides the glass door from the wall to the middle and right to left (from viewer's perspective). But when he closes it, he closes it from right to left so it closes in the middle, even though it wasn't set up that way.
Continuity mistake: In the opening credits, as the room becomes animated, Ricky has a coffee mug an inch away from him. The mug moves a good 10 inches away from Ricky the shot after Karl says "All right?" (00:00:35)