Clash in the Coliseum: Part 3 - S3-E34
Character mistake: When Yugi discards the last card in his hand after activating Spell Textbook, Slifer the Sky Dragon's attack points go from 1000 to zero. This makes Kaiba say, "Now that Slifer's attack points are zero, you'll lose the duel." However, at this point, Yugi has 3000 life points and Kaiba's Obelisk has 4000 attack points, so Kaiba still would have been able to win the duel if Slifer had 1000 attack points, as there would have been a 3000 point difference between the two monsters. (00:18:02)
Clash in the Coliseum: Part 3 - S3-E34
Character mistake: When Kaiba activates Card Guard, he says he can discard two cards from his hand to protect his monsters from Yugi's attack. However, he only sends one of the cards in his hand to the graveyard instead of two. (00:08:57)
Clash in the Coliseum: Part 3 - S3-E34
Character mistake: When Slifer the Sky Dragon's attack points go from 2000 to 3000, Kaiba tells Yugi, "But now that your turn is over, Obelisk regains its full strength," but Yugi's turn isn't over; it only just started, as shown by him activating Pot of Greed shortly after. (00:05:08)
Brothers in Arms: Part 3 - S3-E19
Character mistake: When Noah uses the Gradius' Option card, he says, "I play the magic card Gradius' Option," but the card appears to be a monster card and not a magic/spell card. He is even showing placing it on one of the monster card slots on his duel disk. (00:09:17)
Character mistake: Yugi runs up to a door that includes a four-star monster and is also shown to have been equipped with five face-down cards. After Yugi realises he only has a few cards left, Pharaoh tells him, "Defeating a four-star monster plus four face-down cards is no easy task," but it was established that the door has five face-down cards, not four. Pharaoh even mentioned this a few seconds ago when Yugi first approached the door. (00:12:33)
