I've seen the film. Interesting atmosphere, digital effects are somewhat dated (think 90ies video), practical effect are fine. I am not a manga reader, so it may have flown over my head.
Wow, I wasn't expecting to find a reference to a horror manga in the comments of my post about (what I believed to be) innocuous spirals! That's amazing, although I'm too squeamish to try and read it!
He makes interesting horror stories. I don't usually like horror but I have read some of his work. Another one, by him, that has stuck with me is a bonus story of Gyo called The Enigma of Amigara Fault.
ps: how funny, your description reminded me of a nightmarish manga about a strange hole in a mountain, and .. it was by junji ito https://www.scaryforkids.com/enigma-of-amigara-fault/ (I forgot who the author was until right now)
https://en.wikipedia.org/wiki/Uzumaki_(film)