Character mistake: When we first see Sophie her body was slumped over (the spell to make her old) but later on in the movie, her back magically seems fine. (00:00:01 - 01:50:00)
Character mistake: When Yugi's achievements are being broadcast, the narrator talks about Yugi's victory at the Battle City Tournament and then says, "Yugi defeated former champion Seto Kaiba to win it all." While he did duel Kaiba at the Battle City finals and win, he only defeated him in the semi-finals. The final Battle City duel was between Yugi and Marik, whom he beat in the duel, winning him the tournament. (00:05:58)