I read a critic review that had described this film as 'not having much to say' - and I literally couldn't disagree more. This is such a dark yet deep, well-told and intricate story. The first time I watched it I didn't stop thinking about it for a week. I'm a fan of films that tell really interesting stories. It very much does this, so if you're solely an action fan it might not be for you. But if you're more of a fan of films such as The Revenant (2015) this might be more your pace. At times it's disturbing, but never so much I feel like turning it off (I don't like gory horrors). I'm not great with words so I can't say a lot more. TLDR; Never read critic reviews before watching a film. if the trailer looked good to you, give this a chance.
Edit: forgot to mention, the acting is A*****