Complete the game on Easy Difficulty
Unlock all the unlockables
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
Kill 2 aliens with one Rocket
Destroy the gas station
Kill 15 enemies on the HMV turret
Survive the pool attack
Kill 20 enemies with a sniper rifle
