Damn it. It 's an incredibly idiotic decision in chapter 8 to focus on one girl . This is not conditioned by anything at all . The author just smoked a joint and decided to do so . Focus on Sage she called us a dude to fuck. The author himself does not know where to lead this story after popularity .
For example, I took a screenshot of my saves with 1 particular playthrough I had where I get to pick from at least 12 other girls by selecting the others route before heading into the Halloween event.
My choices before that ending was Bella or others, where Nora Jade Sage and a heap of other girls were possible.
So now I go into the last episode unbound by any 1 girl, and I can chase almost anyone I wish. It's all about the choices.
But if you play the game just minding on 1 girl and refusing everyone else, you're not going to have much to pick from at the end. They're not real girls, so don't be afraid to break Jill's heart, if that's what stopping you from exploring other girls..
Ok, I'm sorry. that was a dick'ish way of explaining it, but I'm sure you get the idea.
Have fun exploring bud.