I’ve played that Demi Lovato game and I noticed they had a bar for fans make a choice you get more fans well I wanna do something similar but not for fans for relationships?
Perhaps check out this: The Points System
You could use a Points system in your story so readers can unlock certain scenes : )
You could use the point system… which @JemU776 has just linked you to. If you wanted an actual bar to show up, you could use on overlay. Have you read Songbird? I forget the author but it was one of the contest winners for the Hero’s and Villains contest and she did something like that.