Complete the game on Easy Difficulty
Unlock all the unlockables
Kill 2 aliens with one Rocket
Complete the game on Normal Difficulty
Complete a mission on Normal without dying, failing, restarting, or continuing campaign
Watch an unlocked video
Complete the game on Hard Difficulty
Call in the airstrike to defeat the Command Center
Destroy the gas station
Kill 15 enemies on the HMV turret
Survive the pool attack
Kill 20 enemies with a sniper rifle
