Use a large medkit to heal an injury of 5% or less.

Customize 25 weapons.

Kill an Infected with a grenade blast.

Find 120 collectibles.

Complete act 2.

Heal yourself with a medkit 100 times.

Create weapons to rival the gods of fire or thunder.

Set 10 zombies on fire simultaneously.

Finish 75 quests cumulatively.

Find 60 collectibles.

Kill a Suicider with a grenade.

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

Create a customized weapon.