I always thought the Purge was a really cool concept for a movie series. A 12 hour period, once a year, in which all crime is legal, thus the street become total chaos in which time your friends or neighbours could turn around and butcher you over any slight. I felt that the first movie wasted its premise by restricting it to a home invasion movie, but its two sequels more than made up for it in terms of action and fleshing out the concept.
It’s a shame that by the time movie number four rolled around, they seemed for forget how creative they could have been with this idea. The First Purge ignores all of the things that made the previous movies so interesting and boils it down to a weak action movie with even weaker social commentary.