Other mistake: On the "Mario's Greatest Movie Moments" DVD of this series, from the main menu, go into the trivia game. The fifth question asks you about the Super Mario Bros. Super Show episode 'Count Koopula.' It asks you "What's room number that the Mario Bros. were put into in Koopula's Castle?" It's supposed to say "What's THE room number that the Mario Bros. were put into in Koopula's Castle?"
Other mistake: When the Marios are hurting enemies and freeing Dr. Nerdnik, Mario kicks through a gate at the start of the scene in order to get inside. This gate disappears, once when Bunsun pushes the doctor through the hole, and twice at the end of the scene. (00:04:45 - 00:06:30)