So my progress of this game is 75% so far. I literally got all the endings I could get thanks to Otakulair walkthrough but unfortunately some of the endings guide were missing in aforementioned walkthrough. Now I wanna aim for 100% and go for the remaining endings which involves Kokoro that I haven't got yet: "Gift from my Father" , "Rain of Carnage" and "Substitute" . Since these 3 endings highly depends on seducing Makoto by Kokoro I somehow stuck on one of choices which is "I do think of her that way" ... whether I chose this or not, what happens after that crashes the game; To be specific I mean where Kokoro tries to render Makoto unconscious by throwing an object at him, that's where exactly the game crashes. I tried to start the game from the beginning several times hoping to find a workaround for it but couldn't manage so far. My game version is uncensored 1.01e Final already and I change the priority and affinity of the game in task manager every time I start the game.
Aside from that I couldn't find a proper guide for these 3 endings. I'd appreciate if someone who had got these endings or simply finished the whole game or have a solution for this weird crash to help me with this issue.
The game crash part is difficult but best I can suggest is playing the game not in fullscreen and do those CPU priority steps which you've probably already done considering you're not complaining about the game crashing every 2 minutes. If that doesn't work maybe try skipping past the scene with the arrow keys or reinstalling the game.
As for the endings, all 3 of those are part of the same branch where you first need to sexually assault Kokoro during that part at the beach you're talking about so just pick all the choices that mean Makoto is attracted to her and she should fail to knock him out at first but succeed eventually. Now Kokoro is scared of him and you just need to ruin your relationship with Setsuna to make sure you don't get any of her endings.
If you do that, instead you'll get a scene where Makoto runs into Kokoro on the street, she'll run from him, he'll chase after and now if I remember correctly you get a choice to tell at Setsuna's father to stop her, pick that. Now you get 3 choices (don't remember the exact wording), 2 of which should lead to the "Substitute" ending and "Rain of Carnage" respectively.
The "Gift from my Father" ending should be some combination of this while being friendly enough with Setsuna since in this ending her father helps fix their relationship after that scene when you let Kokoro go. I unfortunately can't be more help than that but it's the same ending where Makoto goes to Paris with maybe 2 lines different so you're not missing much.