Finish first playthrough
Finish a playthrough without firing bullets (Melee & explosions only)
Finish a playthrough without dying
Complete 10 challenges
Get 200 headshots
Get 500 headshots
Get 1000 headshots
Die only 25 times or less
Die only 10 times or less
Kill all snipers
Get 10 knife throw kills
Get 20 knife throw kills
Get 50 knife throw kills
Detach 5 heads
Detach 20 heads
Detach 50 heads
Kick 100 times
Kick 250 times
Kick 400 times
Finish a playthrough in under 20 minutes