Preview of pregnant Crania, she's not a different person, but it will be considered as a different playable character, it was done mainly to add a new girl to test the new features involving two girls.
On future versions new girls will be playable, and also, you might not know this, but Crania has a twin sister, she might join the party in the future, along with some other girls.
Like i said the theme of the game are supernatural girls and locations, so the next playable girl could be a Demoness or a Witch.