I just found this on Amazon and watched it without knowing a thing about it. I recommend other people go in blind the same. Think in the vein of Split.

This film was so unique and well-acted. Yes, it is quite silly, but I think they're aware and it shows. I was pretty gripped, honestly. It doesn't really rely on gore, nor jump scares. It's more or less a quirky thriller with 2 great performances.

Highly recommended!