Endless Ocean - Cheats

At Ship's Rest at night after you've found the Shark Tooth.

The Water is Wide: Unlocked by watching the credits.
Shenandoah: Unlocked by entering "The Great Aqua Cave".
River of Dreams: Unlocked by entering the White Room of "The Great Aqua Cave".
Pokarekare Ana: Free the bottlenose dolphin from "The Lagoon".
Hine e Hine: Cave in the roof of "The Ruins".
E Pari Ra: Unlocked by visiting "Ship's Rest".
Benedictus (Hayley Westenra): Unlocked by visiting "The Abyss".
Amazing Grace: Unlocked by visiting "Mo'ia Atoll" ruins.
Hayley's Medley: Unlock all the other songs.
Hayley's Medley song consists of all of Westenra's songs in random order.

When it's sunset in-game (after 6pm - use the clock in the boat's cabin to see the time), sit on the deck chair, and look out over the horizon as usual to view a special cut-scene with Staff Credits.