it's the third act that actually saved it I watch tons of horror movies, it's my favorite genre so I'm hardly surprised, watched this expecting a typical possession/haunted house flick to pass time and it has all the cliches for the first half: You get the kid with creepy imaginary friend (Exorcist anyone?), weird presence in the house, kid draws a spooky figure!! I was a bit bored by it until it actually starts revealing what's all about, and it elevates what could be just another mediocre jumpscare filled haunted house. I'll talk about the final act in a spoiler-filled paragraph next, stop now if you want to have a better experience:
The film slowly starts to unveil some kind of family mystery around the whole 'imaginary friend' and the direction does a decent job to keep their cards hidden until the right moments, it shifts focus from the kid to his mother. We know the entity appeared when she was a child and managed to suppress it for years until it returns for her son, things get worse, their house burns down and her husband dies, in order to save her son she offers herself to the creature and isolates in the house with it, even.. sleeping with it? There's an element of her father who commited suicide as well, a subtle clue that this is actually a child abuse tale disguised as supernatural flick, the "monster" is a manifestation of her traumatic relationship with her father, and how her mental illness destroys her life, there's a priest that tries to help her but she ends up consumed by depression and takes her life, a bleak ending to a movie I wasn't expecting to get so dark. Z is in the same vein of Babadook and Relic, which uses monsters and horror tropes to talk about mental illnesses, only not as well crafted as those but still not a bad effort.