Posted below are the best decks I could ever build for Yugioh Forbidden Memories, both for a deck I built without using any Gameshark cheats and a deck I built using cheats.
Natural Deck:
3x Meteor Black Dragon
3x Blue-Eyes White Dragon
3x Twin-Headed Thunder Dragon
3x Sanga of the Thunder
3x Red-Eyes Black Dragon
3x Meteor Dragon
3x Megamorph
3x Bright Castle
3x Dragon’s Treasure
3x Invigoration
3x Salamandra
3x Raigeki
1x Umi
3x Widespread Ruin
I altered this deck by taking out the 3x Seiyaryu and 3x Skull Knight, replacing them with 3x Salamandra and 3x Widespread Ruin. I did not have enough power ups to beat Seto 3rd (with his Blue-Eyes Ultimate Dragon) consistently enough for my taste. Yes, I beat him with my old deck on a 20:1 ratio basis, but I beat with him with my new deck around a 25:1 ratio. It is slightly higher, and I can’t figure out any way to get higher without cheats. This is my very limit.
Skull Knight is a good tech-in for beating Meteor Black Dragons and Blue-Eyes Ultimate Dragons, but I didn’t have room for him. Same with Seiyaryu; plus I don’t need it, since I have enough dragons to fuse with my Sanga of the Thunder to make Twin-Headed Thunder Dragons.
Widespread Ruin saved my life many times, since the opponent often has to waste a turn getting rid of it with Harpies’ Feather Duster or fodder. This gives me a little more time to get a good hand so I can play a strong combo. I usually set it on the first turn, or set it to protect a strong monster I have in play so Seto 3rd (or Nitemare) can’t kill it with Blue-Eyes Ultimate Dragon. If you want to beat this game consistently, you must always be ready to jump against a Blue-Eyes Ultimate Dragon.
Gameshark Deck:
3x Blue-Eyes Ultimate Dragon
3x Gate Gaurdian
3x Meteor Black Dragon
3x Black Luster Soldier
3x Magician of Black Chaos
3x Megamorph
3x Bright Castle
3x Dragon’s Treasure
3x Dark Energy
3x Sword of Dark Destruction
3x Raigeki
3x Swords of Revealing Light
1x Dark Hole
3x Widespread Ruin
I edited the Gameshark deck by giving it a more definite theme: dragons with dark warriors, so I could make the deck more consistent. I could more easily match my monster with the proper equip spell to make it stronger. Black Luster Soldier and Magician of Black Chaos are weaker than Perfectly Ultimate Great Moth and Black Skull Dragon but they can easily become stronger with equips. I traded some strength for lots of speed.
Black Luster Soldier is the strongest warrior in the game after Gate Guardian, and both monsters combine with both Dark Energy and Sword of Dark Destruction. Magician of Black Chaos works as a solid tech-in since you can give it an extra attack boost against a Blue-Eyes Ultimate Dragon or Perfectly Ultimate Great Moth by choosing the right guardian planets when you play it.
Skull Knight also works fine, since it can subvert your opponent’s Meteor Black Dragon with the Neptune guardian planet, but cannot repel a Black Skull Dragon. I would say Skull Knight is slightly more useful than Magician of Black Chaos, since Meteor Black Dragon is a bigger threat later in the game, but I wanted to give my deck a bit of Atem’s character by putting both his ace monsters in it. Too each his own.
Zarathustra the Serpent 