I will give it 3/5, it's not bad, it's is a bit untraditional horror flick in a good way "the storytelling". It is not quite scary, but yes the story is strong and convincing. Pretty simple movie, the first half is almost like a slow paced drama movie but it catches an adequate pace after that.
Not the average horror with typical jump scare and gore.
Worth watching, don't have high expectations only then you might find satisfying.