On every Duel Monsters card is an eight-digit password on the lower left corner directly below the card's picture. Enter this code at the "Password" option on the main screen, and the card will be recorded into your card collection. Note: You can only enter the password once.

In order to unlock Yami Yugi, beat DarkNite 5 times

Beat each duelist in Ancient Egypt five times.

To get decent cards, ( most of the time they're good!) go to the password mode. Then input 65437205. (this may be off, but it worked for me!) Yugi's grandfather should appear and say, "You've found me! I guess I should give you cards from now on...". When you win a duel against an opponent, Tea` should give you a card. (duh) But, afterwards Yugi's grandfather should give you a powerful magic or trap card. This is a cool cheat if you are a beginner, but it doesn't matter to me, for I have the strategy guide book which tells me every card number/ATK/DEF! HAHAHA!!!

In construction mode, where you select cards that have a star on top and bottom, press start to get a new set of numbered parts for construction. (NOTE: You must press start again the next time that you enter Construction mode, Or you can simply hit START again to go back to the other set of card parts)