In the beginning of the film, it is said that Yugi defeated Seto Kaiba to win the finals of the Battle City Duel Monsters tournament on the televised recap of the tournament. However, Yugi's true opponent for the finals was Marik Ishtar / Dark Marik as all scenes that follow the headline show Yugi receiving The Winged Dragon of Ra from Marik.
When Kaiba uses the 'Shining Nova' effect of "Blue-Eyes Shining Dragon" to destroy "Pyramid of Light", although the attack failed, "Blue-Eyes Shining Dragon" disappears, and later Yami Yugi activates "Monster Reborn" to Special Summon it from the Graveyard. However, "Blue-Eyes Shining Dragon" is shown to appear next to Anubis for a short time, after it had already been destroyed following the activation of its 'Shining Nova' effect.
In the Japanese version of the movie, when Yami Yugi Summons "Magician's Valkyria" and attacks "Peten the Dark Clown", he's briefly shown to have "Magician's Valkyria" with "Premature Burial", "Mage Power" and 2 face-down cards. However, that's the field he has 1 turn later, when he revives "Magician's Valkyria" to face "Blue-Eyes White Dragon".
Yugi shouldn't have been able to recall "Blue Eyes Shining Dragon" using the "Monster Reborn" card as it is known as a Nomi monster (meaning that the only way you can use it is if you meet specific conditions and cannot be summoned or special summoned in any other way). The actual card text stipulated that this monster could not have been summoned except by tribute of a "Blue Eyes Ultimate Dragon".
When "Peten the Dark Clown" is destroyed by battle, Kaiba activates "Deck Destruction Virus", which can only be activated when a Fiend-Type Monster with 500 ATK or less is destroyed by battle. "Peten the Dark Clown" is a Spellcaster-Type monster.
When Kaiba stated that the ATK of "Blue-Eyes Shining Dragon" increased by 300 for each Dragon-type monster in his Graveyard, he forgot about "Paladin of White Dragon", which is Dragon-Type as well. So the ATK of "Blue-Eyes Shining Dragon" should have increased to 4800, which would have been more than enough to destroy "Sorcerer of Dark Magic", causing Yami Yugi to lose the Duel.
When "Sphinx Teleia" destroys "Obnoxious Celtic Guardian", "Sphinx Teleia's" effect wasn't activated, which would have decreased Yami Yugi's Life Points to 0. However, when "Andro Sphinx" destroyed "Watapon", its effect was activated (this was not changed when it aired in Japan, though Yami Yugi did mention it). In addition, "Obnoxious Celtic Guardian" should not have been destroyed thanks to its effect; the ATK "Sphinx Teleia" was higher than 1900.
- However, in the original film, Anubis said that it was too soon for Yugi/Yami Yugi to lose the duel so quickly, which may imply that he could control the effects of his monsters.
Pegasus did not need to activate the trap card "Ultimate Offering" to summon additional Toon monsters. At the cost of 500 LP, a player can perform an extra normal summon or set using it, but Toon monsters are a type of monster that can special summon themselves from the hand and aren't normal summoned.
When "Familiar Knight" is attacked, the card underneath is reversed.
When Seto and Pegasus draw due to "Card of Sanctity", "Dark Magician Girl" can be see in Pegasus' hand instead of "Toon Dark Magician Girl".
Several cards shown in the movie do not have the proper font for their card names when their cards are played.
When Yami Yugi Summons "King's Knight", the text on "Queen's Knight" is displayed backwards.
When the duel between Seto and Pegasus begins, the latter is shown with 4 cards in his hand. As per the trading card rules you must begin the game with 5 cards (though the next shot shows the correct amount of cards in his hand).
In the English version of the movie, during Yami Yugi's final turn after his Draw Phase, "Exchange" and "Diffusion Wave-Motion" are visible in his hand though he later activates a card called "Double Spell" which he was never shown to possess in his hand ("Diffusion Wave-Motion" was shown by mistake). In the Japanese version of the movie, it was fixed to show "Exchange" and "Double Spell".
When Kaiba has his computer run a simulation of a duel between him and Yugi, Yugi is listed as using "Paladin of White Dragon".
Right after the opening title, many people are watching a television screen showing Yami Yugi dueling Seto Kaiba , which shows him drawing Exodia's head, but the card is in Japanese.
Seto Kaiba's plan for a 'perfect victory' by Summoning all 3 of Yami Yugi's Egyptian God cards would not normally work, as "Return from the Different Dimension" only affects cards removed from play that you possess. Since they were Yami Yugi's cards, Kaiba would be unable to Summon them. It is possible that Kaiba probably had another strategy to make "Return from the Different Dimension" work with Yami Yugi's monsters.
During the simulation, "Slifer The Sky Dragon"'s effect doesn't activate when Kaiba summons his "Blue-Eyes Ultimate Dragon".
When Yugi uses Kaiba's "Return from the Different Dimension", he mentions how Kaiba wanted 'a perfect victory', but Kaiba never said that - he only thought it.
When Peten the Dark Clown attacks the Pharoah, he stabs him through the back; however, Kaiba calls the attack "Bloodlust slash"; this is incorrect as a slash leads to a cut, not a puncture.
When Kaiba and Anubis argue over how to defeat Yami Yugi, they both mention they could win the duel there and then, but with the way the field was, there's no way Kaiba could have won on that very same turn.
Anubis frequently mispronounces the name of his monster "Theinen the Great Sphinx" as "Thenien the Great Sphinx".
The boy dueling Joey outside of the school mispronounces his monster card's name as "Fenril", when the card is called "Fenrir".