100 headshots.
You've reached level 5.
You've unlocked all images.
You've unlocked all videos.
You've killed 20 zombies.
You've killed 50 zombies.
You've killed 75 zombies.
You've killed 100 zombies.
You've killed 150 zombies.
You've killed 300 zombies.
You've reached level 3.
You've reached level 2.
You've reached level 7.