Really great to see Hugh Grant tackling something way beyond the foppish roles which are (were!) his trademark. The movie offers an excellent exploration of faith, wrapped up in a menacing and intriguing plot of twists and turns.
I liked it less as the menace turned into violence. For me, it lost its intellectual credentials and became a moronic slasher movie, as if to please some dimwit psychopath who might be lurking in the audience.
Still, well worth a trip to the cinema. Very, very watchable.