If you loved Grotesque, try Occult
A bridge between a film you've already seen and one most people haven't. Occult has roughly 3.5× fewer votes than Grotesque — it's a deeper cut, not a mainstream recommendation. Here's what they share, and what the second one does that the first one doesn't.
What they share
Both films are directed by Koji Shiraishi, and they both carry the dread, late night mood tags, and they sit in Horror / Thriller territory. If that's the register that drew you to Grotesque, the second film will land in a comparable space — through a different lens.
dreadlate night
What Occult is
Snow falls on a deserted lakeside resort. Survivors whisper of waking visions. The camera lingers on a pocket watch stopped at 3:27.

