Completed 'Eagle Eye Engagement' Challenge level with a grade of 'B' or higher.
Completed 'Aerial Assault' Challenge level with a grade of 'A' or higher.
Completed 'Tougher Than Nails' Challenge level with a grade of 'S' or higher.
Completed 'Unstable Ground' Challenge level with a grade of 'A' or higher.
Completed 'Undead Attrition' Challenge level with a grade of 'B' or higher.
Completed 'Close Combat Clash' Challenge level with a grade of 'A' or higher.
Completed 'Living Nightmare' Challenge level with a grade of 'B' or higher.
Killed a Skinny for the first time in Survivor mode
Killed a Hound for the first time in Survivor mode
Killed a Winged Horror for the first time in Survivor mode
Completed 'Stone Age Struggle' Challenge level with a grade of 'S' or higher.
Killed a Cheerleader for the first time in Survivor mode
Killed a Flesh Beast for the first time in Survivor mode
Earned the shotgun for the first time in Survivor mode
Completed 'Poor Equipment' Challenge level with a grade of 'B' or higher.
Completed 'Napalm Warfare' Challenge level with a grade of 'A' or higher.
Killed 100 Zombies in a single game in Survivor mode
Killed 200 Zombies in a single game in Survivor mode
Completed 'Engineer Prodigy' Challenge level with a grade of 'B' or higher.
Completed 'High Tech Horror' Challenge level with a grade of 'B' or higher.