Binding of Isaac Achievement: Marbles
In-Game Secret Number
Alt stage to the depths.
Defeat It Lives 21 times
Get a 3-win streak
Defeat Delirium as Cain
Defeat Ultra Greedier as ???
Defeat Little Horn 20 times
Unlocked a new starting item.
Complete challenge #31
Sleep in 10 beds
Collect every entry in the Bestiary (Bugged v190 - Mobs that don't exist in the bestiary are being counted. This allows Sin Collector to be unlocked without a complete bestiary)
Defeat Ultra Greedier as Isaac
Defeat Ultra Greedier as The Lost
Unlocked even more bosses!
Defeat ??? as 6 different characters
Have both the Broken Watch and the Stop Watch in your collection
Defeat Delirium as Samson
Beat chapter 1 without taking damage
Complete a floor after Basement I, start-to-finish, with only half a heart of health (can use The Lost)
Defeat The Lamb without taking hearts, coins, and bombs through an entire run
Unlocked super special rocks.
Get a 5-win streak, using a different character for each win
Complete the Boss Rush as Apollyon
Use cards and runes 20 times