Heal yourself with a medkit 100 times.

Complete act II.

Kill 10 zombies in a row with headshots.

Complete 25 quests while playing with at least one co-op partner.

Kill 250 zombies using blunt melee weapons.

Reach level 25.

Customize 25 weapons.

Save 5 people besieged by zombies.

Complete 5 quests in a single co-op game with the same partners.

Kill 250 zombies using edged melee weapons.

Create weapons to rival the gods of fire or thunder.

Kill 250 zombies with modified weapons.

Kill 25 zombies with your bare fists.