Why will ???/Bluebaby not unlock?
SO, I have around 19 hours played already on afterbirth plus and have defeated mom's heart 13 times, but it is not being replaced by it lives and will not unlock blue baby / ??? please help
"???" also known as "Blue Baby" Is unlocked in Rebirth, not in Afterbirth Plus. This character is unlocked by defeating Mom's Heart 10 times. Note that Rebirth, Afterbirth, and Afterbirth + are all seperate, as noted in the the-binding-of-isaac-afterbirth+ tag.