Ending 20, named "Ultimate Ending" prior to The Binding of Isaac: Repentance, is unlocked just after defeating the boss Delirium, who's Isaac's illustration on the "mild at the end of the tunnel".[16] It builds upon events observed in Endings 12, 15, and 17, and demonstrates Isaac recalling his Recollections in https://liberty-cap-grow-kit75073.goabroadblog.com/28073947/5-essential-elements-for-tboi-liberty-cap