If you loved In the Mouth of Madness, try Someone's Watching Me!
A bridge between a film you've already seen and one most people haven't. Someone's Watching Me! has roughly 11.9× fewer votes than In the Mouth of Madness — 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 John Carpenter, and they both carry the paranoid mood tag, and they sit in Horror / Mystery territory. If that's the register that drew you to In the Mouth of Madness, the second film will land in a comparable space — through a different lens.
What Someone's Watching Me! is
Las Palmas high-rise lobby light buzzing midnight, the elevator’s floor indicator the only noise. She unpacks boxes in number 2403. Next morning the mirror shows her hairbrush moved half an inch. Karen Carpenter’s 1978 paranoid spiral lurks in every staircase.

