It works if you give it a chance. The nun herself is creepy looking with hollowed-out, bloody eyes and a rotted looking face. It's a simple but effective makeup job and we get to see it several times throughout the film so you get your money's worth. The horned demon that pops up near the end of The Ghosts of Borley Rectory on the other hand is a fairly obvious spooky mask but just a simple shot.
Being a low-budget film there are a fair amount of talky scenes, but the script has the good sense to put some scares in some of those scenes even if it's just a simple jump scare. And there are plenty of those throughout the film, performed by an excellent cast. The horror in The Ghosts of Borley Rectory never really gets much deeper than that, but sometimes that's fine, every film doesn't have to be elevated horror. It's worth watching.
Being a low-budget film there are a fair amount of talky scenes, but the script has the good sense to put some scares in some of those scenes even if it's just a simple jump scare. And there are plenty of those throughout the film, performed by an excellent cast. The horror in The Ghosts of Borley Rectory never really gets much deeper than that, but sometimes that's fine, every film doesn't have to be elevated horror. It's worth watching.