I don't usually comment on things but I had to make an account for this. My friend recommended me this game and I've been playing it for the past five days(days off are a blessing). I love it more than I thought I would. I'm done with R's and A's and D's route and almost done with X's . The thing is I saw some comments saying that every character has multiple routs . Is there a walkthrough for that? Are there specific key moments where i have to choose a specific option?
I think you're referring to high vs low romance routes for every love interest (the words used in the relationship screen describing your romance are "steady" vs "unsteady"). This is determined through the choices you make in regards to your love interest. As of now, there aren't any official walkthroughs for it, but you're free to ask others for help here if you like!