Complete the following achievements to unlock Xbox Live Gamerscore points.

Achievement	How to unlock
A Legion of Zombies (20 points)	Kill 500 zombies in one level.
Back with the X (10)	Witness Rachel joining the group.
Big Brain Brian (10)	Witness Brain joining the group.
Can't touch this (20)	Complete a Base quest without taking any damage.
Fists of Fury (10)	Kill a mutant with your fists.
Getting to know each other (25)	Complete all character quests or see someone else do it.
Kill a zombie (5)	Kill a zombie.
Master Craftsman (20)	Fully upgrade a weapon with any status effect.
The Collector (30)	Complete 'Dev Card Hunt!' or see someone else do it.
Thought this was a Zombie Game? (10)	Witness Luxo joining the group.
Touch Base (35)	Complete 'Return to the Military Base'.
Watch this! (5)	Use your first Smart Bomb.