Full list of all 12 Battle: Los Angeles achievements worth 200 gamerscore. It takes around 2-3 hours to unlock all of the achievements on Xbox 360.
Complete the game on Normal Difficulty
Complete a mission on Normal without dying, failing, restarting, or continuing campaign
Complete the game on Hard Difficulty
Unlock all the unlockables
Kill 2 aliens with one Rocket
Watch an unlocked video
Complete the game on Easy Difficulty
Destroy the gas station
Call in the airstrike to defeat the Command Center
Survive the pool attack
Kill 20 enemies with a sniper rifle
Kill 15 enemies on the HMV turret