I really liked the little nod to Side B on cassette tapes. Even though I grew up with cassettes, I had never thought about what "Side B" could represent, so I actually learned something while reading your game. 😊
I also really like the core mechanic where your chances of success depend on whether you're acting as the human hero or giving in to the monster within. Combined with the Spool countdown, it creates a great sense of tension as you slowly lose your humanity.
The atmosphere is excellent. As someone who watches a lot of anime (I kept thinking about Kaiju No. 8 while reading), I could easily picture the story unfolding in my head. I'd almost love to see this expanded into a multiplayer version, with one-shots or even a campaign mode... although maybe that's a completely different game. 😄
The only thing I struggled with was the PDF layout. I found it quite difficult to read, and because of that I had to concentrate much harder than usual to understand the game. Personally, I think I would have preferred a four-page layout with a bit more whitespace and a larger font size. It would make the game much easier to read without losing its style.
In any case, I'd definitely recommend including a plain-text version for accessibility. I think it would really help readers who struggle with the current layout while still letting everyone enjoy the fantastic presentation.