The Purge: Anarchy (2014)

One night per year, the government sanctions a 12-hour period in which citizens can commit any crime they wish -- including murder -- without fear of punishment or imprisonment. Leo, a sergeant who lost his son, plans a vigilante mission of revenge during the mayhem. However, instead of a death-dealing avenger, he becomes the unexpected protector of four innocent strangers who desperately need his help if they are to survive the night.

Plot Keywords: bus, assault rifle, sniper, machete, dystopia, psychopath, sequel, revenge, murder, rampage, motorcycle, violence, masked man, apartment, death, survival horror, gatling gun, purge