Question: how to unlock the binding of isaac?
Answer: Isaac : Unlocked by default., Magdalene : Have seven or more Heart-Containers at once., Cain : Have 55 or more cents/pennys at once., Judas : Defeat Satan., ??? aka Blue Baby : Defeat Mom's Heart 10 times., Eve : Beat two floors in a row without picking up any hearts., Samson : Beat two floors in a row without taking any damage.