Perfect Lovecraft horror
The closest to a Lovecraft novel I've seen as a movie. The story could easily pass as an early LC novel. Not just the obvious themes such as the unfathomable cosmic horror that would drive a mortal person insane, but the subtle references such as Pickman's Hotel and the book possibly being a version of the Necronomicon, even characters having visions and dreams about the entities.
As a fan of horror movies, it's decent and entertaining. As a fan of Lovecraft, it's genius