Impmon:
Complete the game with all three season three characters.

MegaGargomon:
Enter the password MINNYN.

Omnimon:
Enter the password SERIUS. Or complete the game with Gabumon and Agumon.

Reapermon:
Complete the game once.

Gallantmon:
Enter the password KIMJOY.

Imperialdramon:
Enter the password LINMON.

Imperialdramon (Paladin mode):
Enter the password ROYBOY. Or complete the game with both Veemon and Wormmon in first, second, or third place.

Sakuyamon:
Enter the password KENSAN. Or complete the game with Renamon.

WarGreymon:
Enter the password QRIOUS.

BlackWarGreymon:
Play the game on any difficulty setting without losing a round (not a continue). During the fight with the last Digimon before Reapermon, BlackWarGreymon will challenge you. Beat him and Reapermon without losing a round to unlock him.

Get digivolved form:
To receive anyone's digivolved form, complete the game with them.

Get Mega form:
To receive anyone's Mega form, complete the single player game with that person. You cannot be a Mega in single player mode

Select same Digimon twice:
Choose any Digimon at the character selection screen. Then, go back to the Digimon you chose and hold Select + X.
Alternately, successfully complete the game then choose two player mode. Press L1 + R1 on controllers one and two to select the same Digimon.

BlackWarGreymon:
Play the game under any difficulty setting without losing a round (not a continue). During the fight with the last Digimon before Reapermon, BlackWarGreymon will challenge you. Defeat him and Reapermon without losing a round to unlock him.

Young Digidestined:
At the character selection screen, hold L1 + L2 + R1 + R2 for young (or old) digidestined. Note: This only works with Wormon, Stingmon, Gabumon, Metalgarurumon, Agumon, Wargreymon, Patamon, Seraphimon, Gatomon, Magnadramon, and Omnimon.

Alternate music:
When you use the "Young Digidestined" code and choose the Abyss stage, different music will play. If you combine the Digidestined (first season and second season), it will play various songs.