Eagle Eye Engagement
Completed 'Eagle Eye Engagement' Challenge level with a grade of 'B' or higher.
10 
Grounded
Killed a Winged Horror for the first time in Survivor mode
10 
Stone Age Struggle
Completed 'Stone Age Struggle' Challenge level with a grade of 'S' or higher.
10 
Undead Team Spirit
Killed a Cheerleader for the first time in Survivor mode
10 
The Fat Zombie Sings
Killed a Flesh Beast for the first time in Survivor mode
10 
Aerial Assault
Completed 'Aerial Assault' Challenge level with a grade of 'A' or higher.
10 
This is my boomstick!
Earned the shotgun for the first time in Survivor mode
10 
Poor Equipment
Completed 'Poor Equipment' Challenge level with a grade of 'B' or higher.
10 
Napalm Warfare
Completed 'Napalm Warfare' Challenge level with a grade of 'A' or higher.
10 
Zombie Slaughter
Killed 100 Zombies in a single game in Survivor mode
10 
Zombie Massacre
Killed 200 Zombies in a single game in Survivor mode
10 
Engineer Prodigy
Completed 'Engineer Prodigy' Challenge level with a grade of 'B' or higher.
10 
High Tech Horror
Completed 'High Tech Horror' Challenge level with a grade of 'B' or higher.
10 
Tougher Than Nails
Completed 'Tougher Than Nails' Challenge level with a grade of 'S' or higher.
10 
Unstable Ground
Completed 'Unstable Ground' Challenge level with a grade of 'A' or higher.
10 
Undead Attrition
Completed 'Undead Attrition' Challenge level with a grade of 'B' or higher.
10 
Close Combat Clash
Completed 'Close Combat Clash' Challenge level with a grade of 'A' or higher.
10 
Living Nightmare
Completed 'Living Nightmare' Challenge level with a grade of 'B' or higher.
10 
Not so fast
Killed a Skinny for the first time in Survivor mode
10 
There Goes the Hounds
Killed a Hound for the first time in Survivor mode
10