Complete the first mission

Complete the game in 6 hours or less

Use every weapon in the game

Sever 100 limbs.

Kill a Suicider with a grenade.

Kill an Infected with a grenade blast.

Travel a distance of 20 kilometers on foot.

Save 5 people besieged by zombies.

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

Reach level 10.

Join another player's game.

Kill 25 zombies with your bare fists.