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

Happily Ever After (30 points): Complete the game.
PWNT! (5 points): Defeat an opponent on your first turn during any single player game mode.
Cheating AI (5 points): Be defeated by an opponent on their first turn during any single player game mode.
OMGHAX (20 points): Make a match of 8 gems in a row in any battle game mode.
Epic Win (10 points): Defeat an opponent while on 1 Life Point during any single player game mode.
Epic Fail (10 points): Lose to an opponent while on 1 Life Point during any single player game mode.
Gate Hacker (20 points): Use the Bash mini-game to destroy every locked gate, door or chest possible!
Save Verloren (5 points): Save the town of Verloren from invading Goblins and Trolls.

Additionally, there are four secret achievements:

King Godd (10 points): Defeat King Godd and complete the 'King Godd' quest.
Shadowbringer (15 points): Defeat the Shadowbringer and complete the 'Shadowbringer' quest.
Dragonslayer (40 points): Defeat the Green Dragon and complete the challenge quest.
Abominable (30 points): Defeat the Yeti and complete the challenge quest.