West's found-footage structure doesn't always entirely make sense, but it's easy to forgive "The Sacrament" its flaws.

The first half is a cautiously dread-inducing tour de force... The second half, however, when all hell breaks loose a little too quickly, is the disappointment.

Everything that happens is what you'd expect, and the choice of subject and the modifications West has made to the generic conventions don't add much to the suspense or thrills.

By focusing principally on the events of the massacre, the characterizations are slightly shallow, but Gene Jones' portrayal of Father and the harrowing use of faux documentary footage makes this intimate and unsettling Jonestown adaptation work