Pass the Undercaves without dying once.
Acquire the Death Sonar.
Ecco the Hero
Rescue the dolphin family in The Lagoon level.
Game Win 2x
Complete the game 2 times.
Reach Ridge Water without dying.
Kill 10 Sharks in a row.
Kill 30 enemies with the Death Sonar.
Pass the Undercaves without being hit by an Octopus.
Songs in the Sea
Find the hidden glyph in Origin Beach ("Never have we heard...").
Game Win 3
Complete the game without dying more than 3 times.
Reach the Dark Water Level without the Death Sonar.
Big Blue Message
Find the glyph in Island Zone that tells you to find Big Blue.