-Muzy (Sound Test)
After defeating the Titan boss in Big Swell, go to Seagull Beach on Windmill Island and talk to the koala with the guitar. You will now be able to listen to music, sound effects and dialogue from the game, and can receive missions which unlock extra sounds once completed.

-Blaze the Cat
Defeat the Kraken boss in Coral Cave (World 3) to unlock Blaze as a playable character.

-Extra Ending