Full list of all 12 0 day Attack on Earth achievements worth 200 gamerscore. It takes around 8-10 hours to unlock all of the achievements on Xbox 360.
Enter the Main Menu
Clear the game on Normal in single player mode
Clear the game on Hard in single player mode
Play a CO-OP Mode game
Kill 10 Sandwich enemies
Kill 10 Snake enemies
Kill 10 Mosquito enemies
Kill 100 targets in CO-OP Mode
Occupy all control points in CONTROL POINT MODE
Get shot down 256 times
Cleared the game on Normal difficulty or harder without losing a life
Earned every rank