Isaac vs The End

Had my damn mic muted, I can't believe I won't be able to see my reaction years later for the final ending to one of my favorite games. 10 years and for what. I love how it shows the lost and forgotten as characters, yet I have NO CLUE as to how to unlock them. I literally have everything for Isaac except Greedier, which I still have no idea how to unlock. Maybe donate more money? lol