Sound test:
Win any tournament with an adult pet. A new icon will appear above your pet's A symbol will appear above your pet on the statistics screen. A music mode selection will now appear on the options screen. Select it for options for a sound test, sound effects test, sound test speed, and a gallery of all pets.

Mimitchi:
Feed a pet that hatched from a black egg only carrots. The pet will transform into Mimitchi after turning six.

Recommended color palette:
Press Right + A at the Game Boy logo when playing this game on a Game Boy Color system.