Survive 50 waves in one run (Singleslayer-only).
Unlock Doc.
Unlock Specter.
Unlock Mechanic.
Unlock Scavenger.
Unlock Dunes.
Unlock Swamp.
Make boomer kill another boomer.
As a Mechanic achieve 500 kills on your turret in a single run without it being destroyed.
As a Specter move zombies 5000 times using your skills in a single run.
As a Doc deal 1000 damage in flames to zombies in a single run.
Unlock all Early Access characters.
Discover D-Barrel surfing.
Survive 30 waves on Typhoon with at least 2 Aberrations in one run.