In all honesty, I think people forget that a horror movie doesn't have to be fast and gorey to be horrific. Horror doesn't necessarily have to be scary in the sense of 'omg i can't believe that just happend'
But it can be scary in the extremism. I hear others say the characters are one dimensional, flat, and not well developed, but that had its purposes that each character was extreme. The extreme idolization of marks date, the extreme pride of all the eaters, the extreme amounts of money, and the extreme class separation. It's not supposed to have you on the edge of your seat its suppose to disturb you in the sense that we've seen people like this in real life and they dont always change even when scared and threatened their nature is their nature and it's unchangeable. It's not about the actual horror elements it's about the message