Complete the treatment plant.

Obtain all keys and use them all.

Shoot down a Hunter or an Eliminator while they are jump attacking in the air.

Fight off the Proto Tyrant.

Defeat Infected Bat.

Complete the training facility.

Create a Custom Handgun.

Defeat a zombie by stomping on them.

Try to push something heavy with Rebecca.

Create a Molotov Cocktail.

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

Complete the train.

Defeat an enemy with a knife.