An interesting idea, held back by the one month development time. It was clear to me through playing, that thought had been put into what the story would be, but the writing and grammar fell flat. Majority of my time reading, or speaking out loud for my video, was spent having to decode how sentences were supposed to be read. It took me out of the moment almost constantly, which is a big disappointment for a game that's supposed to be psychological. I want to be immersed, but it will take more development time to get the game there.
My other criticism would be with the characters. No one stood out to me. Our MC being named Moon felt out of place, considering the game is called Half Moon. I understand you could interpret this as a literal Half Moon, or of the killer being half of him, but it was stated that there are other cases like this. I would've gone with another name, but perhaps it works.
I have more points, but I will leave it at this. Can I really complain too much about a Visual Novel that was only made in a month? I want this game to be truly great. It might be in the future. For now it is not, and I want my critique to serve as fuel to continue improving upon the idea of the "Half Moon Phenomenon" and making changes that will benefit the game going forward.