Here is the full list of all 20 VALA: Vicious Attack Llama Apocalypse achievements worth 1,000 gamerscore.
Kill the entire US & Canada llama population
Cause $100,000,000 of damage to the world
Unlock every perk
Revive a friend
Unlock every weapon
Make 1000 ice cubes
Complete District 3
Complete District 2
Destroy 200 magazine stands
Complete District 1
Kill ovar 9000 llamas
Extinguish 10 llamas that are on fire
Clear 10 sections without missing a shot
Destroy 20 phone booths
Clear 2 areas without using a weapon
Get the framerate down to peasant-level
Knock over 50 street-lights
Wash the camera 5 times
Unlock your first weapon
Kill 30 llamas