Data exists for Battle CDs 00 and 51-60, though they can only be obtained by hacking. CDs 51-55 are incomplete, kicking you out of the challenge upon startup since you don't have a team (the game effectively treats this as a loss). CDs 56-60, meanwhile, are identical to some of the Battle Sim tutorials. Battle CD 00 is the Salamence vs. Metagross battle at the beginning of the game.
The game contains many unused maps, most of them test maps and leftovers from Colosseum, including The Under and Pyrite Cave (though without music, NPCs, PCs or Healing Machines). The chasm in Cipher Lab's subway station now has a bridge over it, which could mean the area was meant to return. Also, it was apparently once possible to enter Greevil's cruiser while it's docked on Citadark Isle.
There's an unused item for "The key to the safe in the Parts Shop," and map descriptions for both The Under and Dark Colosseum, "A Colosseum built on Citadark Isle."
Through Action Replay codes, the player can start the game with a Lv. 26 Jolteon and a Lv. 30 Vaporeon instead of a Lv. 5 Eevee. Like the starter Eevee, they are listed as "Obtained from Michael's dad."
God Never Said That: When covering the game, Chuggaaconroy stated in one episode that the Big Bad was originally meant to be Wes, the Player Character from Pokémon Colosseum, and that this was changed because the developers felt such a thing would be too dark and devalue the plot of Colosseum. There is absolutely no evidence in-game, within the game's code, or via Word of God to back this up, but fans still cling to it because Chugga's penchant to do heavy research on every game he covers means he is an otherwise trusted expert in Pokémon knowledge. Chugga would confirm much later that he fell victim to misinformation, the source turning out to be a Did You Know Gaming parody account.
Keep Circulating the Tapes: Alongside Colosseum, XD has not seen a re-release ever since its original launch in 2005.
Some data left on the disk reveals that The Under was planned to appear in the game, but that the residents DID move out anyways, leaving the town abandoned.
Map Description: "An abandoned underground town."
There is also a map description for a "Dark Colosseum" on Citadark Isle.
Instead of an Eevee, the player was going to receive a Vaporeon and Jolteon as their Starter Mon. Their levels were 30 & 26 respectively, suggesting trainers were going to start off at higher levels and all battles would be double battles like in Colosseum.
Other Trivia:
This is the only Pokémon spin-off title to have its own box unique mascot.
Shadow moves can be either Physical or Special, making XD the first game in the series where moves could be Physical or Special independent of their type.
