I'm glad you enjoyed my directing! Since it's my first work, I decided to make it for free. I hope for many to enjoy it. DN was initially shorter and simpler, but as years passed by, I became perfectionistic and ambitious.
I applaud you for getting most achievements by yourself. I won't release a walkthrough for now because it's too early. The game has only been released 3 days ago and I don't wish to spoil it. As for your question, the hint lies in Kurato chapter 1. You can join my discord group to discuss or ask for help from fellow players! Link in the download page, above the comments.