Complete the following achievements to unlock Microsoft Gamerscore points.

Achievement	How to unlock
Bloody Carnage (30 points)	Complete the story on "Normal" difficulty.
Boner (90 points)	Kill 1000 Skelton Army.
Bored? (10 points)	Played all modes.
Bring The Peace (30 points)	Shoot 250,000 bullets.
Carnage (15 points)	Complete the story on "Easy" difficulty.
Dead No Longer Walking (90 points)	Kill 1000 Zombies.
Dino Crisis (15 points)	Complete Mesozoic Era on story.
Do Not Compute (90 points)	Kill 1000 Robots.
Extreme Carnage (90 points)	Complete the story on "Hard" difficulty.
Frozen (15 points)	Complete 4th Century BC on story.
Greedy (90 points)	Unlock all the weapons.
Headmaster (30 points)	Get 500 Headshots.
I'm Not That Bad (15 points)	Achieve Bronze in all challenges.
I'm Pretty Good (30 points)	Achieve Silver in all challenges.
I'm the Dogs B (90 points)	Achieve Gold in all challenges.
Mexican Wave (30 points)	Survive 25 waves in Arcade.
Mr Robot (15 points)	Complete 6th Millennium on story.
Perky (90 points)	Unlock all the perks.
Shoot Her (90 points)	Kill 1000 Dinosaurs.
Slippery Devil (30 points)	Take no damage for an entire level in the story mode.
Zombie Nation (15 points)	Complete 4th Millennium on story.