Defeat the Proto Tyrant.

Complete the factory.

Complete the laboratory.

Get picked up by the Infected Bat.

Defeat Mimicry Marcus with a Molotov Cocktail or a Napalm Grenade.

Change into a costume.

Defeat a zombie by stomping on them.

Attack an enemy to save your partner who is grappling with that enemy.

Complete the train.

Defeat an enemy with a knife.

Break free of a Cerberus while they are biting you or trying to push you down.

Earn all trophies.