Film review: The Purge - This ultraviolent movie starring Ethan Hawke is totally unconvincing

In this future-set home-invasion thriller "Safe night" is the new "Goodnight". The year is 2022, and crime is way down thanks to The Purge, a 12-hour window in which all criminal activity, including murder, is legal.

Family man Ethan Hawke and his wife (Lena Headey) believe themselves safe in their de luxe locked-down homestead – he's a security-systems executive – until their young son allows a homeless man, tattered and bloodied, into the house.

Next thing a gang of masked vigilantes led by a preppie psychopath is baying for blood outside their front door. James DeMonaco is fine with the stalking and killing part – it's pretty strong meat, with scenes of torture – but less convincing with the rhetoric of salvation.

Upright American citizens claiming to be "cleansed" of hatred by murdering looks foolish unless it's being played as satire – and this ain't satire.