Kill your first Zombie in story mode.

Rid the world of twenty zombies in story mode.

Eradicate one hundred zombies in story mode.

Notch five hundred zombie kills in story mode.

Wipe out one thousand zombies in story mode.

Is it absurd to think you can kill five thousand zombies in story mode? No!

Aww, your first zombie kill in horde mode.

Take out twenty zombies in horde mode.

Destroy one hundred zombies in horde mode.

Reach five hundred zombie kills in horde mode.

One thousand confirmed zombie kills in horde mode.

Five thousand zombie kills in horde mode? Sweet!

Kill ten of the undead minions of the dread Baron Dumorte.

Eradicate ten of the twisted products of Dr. Toten's zombie serum.

Destroy ten of the infested hosts of Cicatrix's symbiote brood.

Take out a Witchdoctor, one of Baron Dumorte's evil, zombie-summoning priests.

Destroy a disgusting, bile-vomiting Spewer.

Shoot down a Magus.

Burst a Bloater, Cicatrix's swollen, symbiote-infested behemoths.

Are they out there? Prove it with a corpse of a Little Grey Man.

Squish one of Cicatrix's slithery Symbiotes.

Kill a Spiker. Watch out for the pointy bits.

Rid the world of that poster child for PEDs, the serum-swollen Hulker.

Dispose of a zombie-infested sky rat, the hideous Seagull.

Turn a zombie Shark into chum.

Unlock the Agent, the Alien, the Scientist, and the Shaman player characters.

Reach level ten for the first time.

Make 100 shots without missing.

Make twenty critical shots in a row.

Kill one hundred enemies in a single horde mode game.

Finish story mode.

Finish story mode in under one hour, thirty minutes.

Kill every type of zombie in the game at least once.