Martyrs (2008)
Like rape-revenge films, New French Extremism is obviously going to be well represented on a list of the most violent horror films. Particularly fruitful in the oughts, these films were notable for their stomach-turning levels of violence. Martyrs is, for me, the most disturbing, and the only movie where I have had to fast-forward through the horror. The lead up to the finale is violent, but the final torture sequence is another level. It has a political/spiritual message at the end, but really this is pure torture porn.