Alphabirth adds new transformations to The Binding of Isaac: Rebirth. Each transformation grants unique abilities to Isaac, and are obtained by collecting a set amount of specific items that are both from the base game and from Alphabirth.
Each additional active charge gives Isaac an all-stats up increase
Batteries have an increased chance of spawning on room clear
Replaces Isaac's health with Black Hearts
Upon death, the "Forget Me Now" effect triggers, respawning Isaac at the start of the floor with 3 Black Hearts
Isaac takes no damage from fire
Upon being damaged Isaac shoots out fires in all directions