Yu-Gi-Oh! Duel Monsters International 2

press R at the password machine and enter password to get card

If you haven't beaten the game, the color of the title screen is normally blue. But after you beat the game, the color switches to purple. You can change it back to blue by pressing Up, Up, Down, Down, Left, Right, Left, Right, B, A at the title screen. Input the same code to change it back to purple.

Every Tuesday, the card shop closes. But every other tuesday, you can find Grandpa Yugi wandering around a random area. You can duel him and his exodia deck at that time.

When playing with an Exodia Deck, If your hand contains, for instance, three of the necessary pieces and Graceful Charity, and you activate Graceful Charity, If you get the final two pieces before you have to discard according to Graceful Charity's effect, and you discard Exodia pieces, the animation for an Exodia victory will play, but the match will be considered a Draw. Weird, huh?

Talk to Weevil Underwood with a deck where the only monsters are insects

Occasionaly the scrolling bar will say "Where is Joey?". When it says this go find Joey and talk to him (Not challenge), and if you own a Time Wizard you will face him in a pure luck duel with weak monsters, dice cards, and Time Wizard

Look for the Scrolling bar to ask if Harpie types are Mai's alone. Construct a deck that contains no monsters with Harpie in their name and no spell cards and she'll duel with you.

When you play this card, normally you destroy your opponent's monster with the highest DEF, but if their monster has 0 DEF, it will actually destroy an empty field zone (Which basically means you wasted it...).

Make an Exodia deck your current deck. Go to the card shop. Talk to Grampa and he will ask you to duel against him using an Exodia deck. Both of the lifepoint scores will start at 10. The only way to win is to get all five pieces of Exodia into your hand. Bringing either players' lifepoints to zero will end the duel in a tie.

As soon as possible, go to grandpas shop, duel and win agains everyone inside his store, talk to him, he will say that you are an impressive trainer and invite you to a mini-championship to sponsor his shop, it's pretty easy, 2 battles against the anime duelists.