Complete a request for the Merchant.

Play Leech Hunter.

Defeat Queen Leech.

Defeat all bosses except Centurion using Rebecca.

Obtain all keys and use them all.

Complete the factory.

Complete the laboratory.

Defeat 16 bats in the church.

Get picked up by the Infected Bat.

Play the piano using Rebecca.

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

Change into a costume.

Defeat an enemy with a critical-hit headshot.