Complete the following achievements to unlock Xbox Live Gamerscore points.

Achievement	How to unlock
Dead...again (20 points)	Achieve your first instant kill on a zombie.
Discoverer I (20 points)	Enter La Vendida Island
Discoverer II (20 points)	Enter La Sonada Island
Discoverer III (20 points)	Enter Santa Barbara Island
Easy survival (45 points)	Complete the story mode in "Normal" difficulty.
Four-handed massacre (20 points)	Complete a local or online challenge with another player.
Herbalist (20 points)	Find the 20 special plants of the Herbarium.
Level Up (20 points)	Unlock your first skill
Perfect run (45 points)	Complete a challenge with a "S" ranking.
Picky monkeys (45 points)	Complete the 12 secondary quests of Kovac's monkeys.
Survival veteran (45 points)	Reach "Survival hobbyist" ranking tag.
Unbreakable (80 points)	Complete the story mode in "Iron man" difficulty.