Major choices:
- Moonsong or Evelyn sex first or second
- take more money and not give to homeless or do
- Lucia love path or not
- Have sex with mimic clone in her own form or in the image of a celebrity
That's all the ones I can think of off the top of my head.
Outside of that, learning to use
URM will help you in most cases in most Ren'py games.
some other important (maybe not major in the grand scheme of things, who knows):
- continue relation with Ev and Moonsong or not
- start relation with Tanya or not
- you can also tell Lucia to fuck off iirc, no relations (haven't tried it personally)
- start relations with Meri or not
- start relations with Ruth (in the new update) or not
I think that covers most of the choices that have some effect on the story.
MC would like to get Lucia's power at some point and he takes one of two approaches to get close to her: MC can try to either soften her up with affection to get to know her, or manipulate her to get her power and treat her as a fucktoy as a sort of revenge for her bulling the other girls.
the trigger for this is the convo with Evelyn when she sees her pictures in the morning (manipulate or not) in case anyone is wondering