I just finished coding the "alignment change" effect:
posted a video on twitter but the quality is rather poor, in game looks better.
I am not sure if to keep a scale of 9 steps or not. In practice there are choices that give +1 light/dark, and others that give +2 light/dark. Then during the story, and in particular at the end of the game, there are checks for those values, and depending if Amber is more "light" or "dark", things will change.
Since I check only if light>dark (and viceversa) I think that 9 steps should be enough. This way you can still change things even later in the game, as long as you have still 2-3 choices to make. And also allows the player to experiment with both light and dark paths.
Some choices instead are fixed, like at the end of each young age romance there's a choice that will impact what happens in the adult age (did you help vampires or report them to authorities? etc).
The only thing I'm thinking if to add, is to have a separate light/dark value for each love interest, since the romance endings are also influenced by this light/dark system, but maybe that would be a bit too much. I need to think
