The Purge manages to be smart, scary, and subversive.

As in so many Hollywood spectacles, the message and medium are at hopeless odds... Still, the set-up is arresting, the domestic scenes well observed and acted, and the payoffs involving that Roomba toy excellent. Also, a late-film twist isn't a surprise, exactly, but it is delicious.

There’s gold in the premise of “The Purge” and its dismissal of subtlety. But like the residents of its world, when given the opportunity, it drops restraint and goes for blood.

James DeMonaco’s blood-splattered thriller begins well before expiring slowly from multiple improbabilities.

What should be a clammy exercise in claustrophobic, queasy tension becomes, in the hands of writer/director James DeMonaco, an underpowered compendium of over-familiar scare tactics and sledgehammer-subtle social satire.