Thank you for playing the first 90 minutes! Sorry I didn't get back to you sooner.
About the Umineko influence; I think that's just me being more of a reader/writer than a gamer, lol; so the linear-ness of the story is just me prioritizing writing than gameplay, at least for this build of the game so far. Although, if you have any suggestions on how to make the player more involved in the story, that would be really helpful.
The locks for the choices in this build are routes which I haven't gotten around to writing or editing them yet, so the locks should only be there temporarily.
As for the seamless bgm loops not working, I replied to Animamendi24 that there was an issue of the engine which broke the seamless loops. However, just recently, I've also noticed that there are some bgm which could be looped perfectly (if one removes the song ending/intro), yet the royalty free music artists didn't bother to make them into loops. I'm in the process of manually editing those bgm into loops, so that I don't have to call the seamless fade function in the code and instead just play the bgm directly.
Again, I really appreciate you playing, even for a bit! I'm glad you've picked up on that Umineko vibe! And it's awesome you are also taking notes on the mystery as well!