Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Undercaves Survival (5 points): Pass the Undercaves without dying once.
Death Sonar (10 points): Acquire the Death Sonar.
Ecco the Hero (10 points): Rescue the dolphin family in The Lagoon level.
Game Win 2x (10 points): Complete the game 2 times.
Life Saver (10 points): Reach Ridge Water without dying.
Shark Killer (10 points): Kill 10 Sharks in a row.
Sonar User (10 points): Kill 30 enemies with the Death Sonar.
Octopus Avoider (15 points): Pass the Undercaves without being hit by an Octopus.
Songs in the Sea (15 points): Find the hidden glyph in Origin Beach ("Never have we heard...").
Game Win 3 (20 points): Complete the game without dying more than 3 times.
Sonar Free (35 points): Reach the Dark Water Level without the Death Sonar.
Big Blue Message (50 points): Find the glyph in Island Zone that tells you to find Big Blue.