Unlock Eternal Mode - All 16 Normal Stages:
At the end of any given stage's Eternal mode score atleast an 80 as your second score then talk to the animal and then select the top choice when given the option. Playing in Eternal mode there is no time limit, to exit Eternal mode and save all items/cousins/presents collected just pause game play and press Square and select the left choice.

Unlockable Soundtrack:
New songs are unlocked by clearing the various missions in the game's Sound Test which is found in the Vacation Memorial. The songs then become selectable during any mission.

Song for King of Kings:
Beat the game (clear the credits once)

Unlock Blue Orb:
Beat the game (clear the credits once)