Its all made by me. My current computer sucks so I am using reason 5, though I own a license for 10. Getting a new computer at the end of the month when payday comes. Yes, there are a lot of clues in the music. All the lyrics are either about what is happening, the themes or something that is going to happen. I am working on my demoupdate at the moment with a whole lot of quality of life fixes but also a lot of new content. Best example I have of the lyrics having to do with the events is this for now (bunch of audioissues created by the recording unfortunately):
Oh, and the singing is programmed using software similar to Hatsune Miku if you know what that is, I am a man ;). It takes a lot of work to make it presentable but its quite interesting to work with. Concerning mood and themes they become more clear as the game progresses. The video I think explains quite a lot of the themes in chapter 1. Each chapter will have different characters, except for our main dude Winter who is like an outside observer moving through peoples experiences.I am going to go through your OST now while I continue to work :).