Wow, I absolutely love this game! I've been playing for hours!!! I really, really like Kurato! I can't seem to get romantic endings- just normal :') But I really love this game!! I'll make sure to support in the future when I can!
His route is the hardest when it comes to making choices for the romantic ending. While he is a very open character, his heart is a tough nut to crack :') There are 2 walkthroughs at the link section. Maybe they can help you to get the other ending.