Revealing mistake: In the opening credits, Beefy Bert has a different hair colour to what he has in the actual episodes. This was not included in Series 3.
Revealing mistake: After Round Alpha-1 concludes in the Inner City Academic Amathalon, Vinnie complains that he should have studied, and his head falls to the table. However, for about 1 frame before his head falls to the table and Rocket grabs his ear, the shadow of his head can be seen on the table while his head stays upright. (00:09:20)
Revealing mistake: When Yugi, Tea and Tristan see the three monsters headed towards them, in the shot where Yugi says "It's definitely not nothing," the front side of the Millennium Puzzle is completely blank and is missing the designs. (00:16:30)