Starring Ethan Hawke and Lena Headey. Rated 14A. Now playing.

On paper The Purge looked promising for horror fans, mainly because it was—as the ads trumpeted—"from the producer of Paranormal Activity and Sinister", two of the better supernatural thrillers Hollywood has spawned in recent years. Plus, it stars Ethan Hawke (who was impressive as Sinister's struggling true-crime writer) and Game of Thrones' magnetic Lena Headey.

The premise of The Purge is that by 2022, Americans are legally allowed to commit any crimes they want one day a year. The government-sanctioned, 12-hour bloodbath is supposed to help the inherently violent society cleanse itself through the release of pent-up frustration and rage.

The thinning of the herd also makes economic sense, because those too poor to defend themselves are the first to be taken out by the more fortunate. The lazy bums shoulda gotten jobs so they could afford pump-action shotguns!

It's a win-win situation for the country's "New Founding Fathers"—and for those who might live in a gated community, like newly rich home-security salesman James Sandin (Hawke) and his family. Sandin believes in the necessity of the purging process, but when his teenage son's compassion makes their household a target of roaming "hunters", things change.

The rest of the film is a checklist of predictable home-invasion antics rolled out in the name of heavy-handed sociopolitical commentary.

Little suspense is generated by writer-director James DeMonaco, who relies mainly on incessant shotgun blasts to get his blunt points across. The uninspired dialogue and vague characterizations make for generally lacklustre performances.

During the scene where Sandin awkwardly wrestles and duct-tapes a fugitive homeless man (Edwin Hodge), it looks like Hawke is trying to hold in a laugh. Or maybe that was just me.

I will give DeMonaco credit for having his mob of Purgers don smiley-face masks, though. The sight of a stranger with a leering plastic grin and a machete standing around in your front yard is unsettling to the max.

At least I know what to be next Halloween.