In Yu-Gi-Oh! Duel Monsters III: Tri-Holy God Advent and Yu-Gi-Oh! Dark Duel Stories, Simon, known as Paradox in this game, appears as a Level 3 opponent, unlockable by defeating all Level 2 opponents at least five times each.
In Yu-Gi-Oh! Duel Monsters 8: Reshef of Destruction and Yu-Gi-Oh! Reshef of Destruction, Simon is named Paradox and has a role in the story. Ishizu will task the player, Yugi and Joey to go to China where Paradox will be. Paradox will inform the player that The Winged Dragon of Ra will need to be unlocked from its Sphere Mode. Later, the player will need to Duel against his Millennium Guardians before facing Paradox himself. In the post-game, Paradox appears as an opponent in the Hall of Eternity.
In Yu-Gi-Oh! Duel Monsters EX 3 and Yu-Gi-Oh! World Championship Tournament 2004, Simon appears as a Level 6 opponent. To unlock him the player must have defeated all Level 5 opponent's at least fifteen times each. They must then defeat any combination of Tea Gardner, Tristan Taylor and Trusdale three times in a row. Selecting any of them for a fourth Duel will result in them Dueling Simon instead.