Sergeant Major
Complete the game on Hard Difficulty
50 
One Hundo
Unlock all the unlockables
50 
Staff Sergeant
Complete the game on Normal Difficulty
25 
Private
Complete the game on Easy Difficulty
15 
Long Range
Kill 20 enemies with a sniper rifle
10 
Color Me Impressed
Complete a mission on Normal without dying, failing, restarting, or continuing campaign
10 
Hummer
Kill 15 enemies on the HMV turret
10 
Rocketman
Kill 2 aliens with one Rocket
10 
Kaboom
Destroy the gas station
5 
Pool and Dive
Survive the pool attack
5 
Droppin Bombs
Call in the airstrike to defeat the Command Center
5 
Seen Your Video
Watch an unlocked video
5