And I really liked it. It was silly, bloody fun with a few standout scenes. Occasionally, there was some subtle acting going on with hints of backstory that will hopefully be explored in the director's commentary.
It passed the Bechdal Test with flying colors and no character annoyed me to the point of wishing them dead... prematurely. If you have a problem with a teen girl vocally questioning and challenging the status quo, maybe that says more about you than the character.
Also, I enjoyed a few details like the armored car that looked like something you'd get from a high school metal shop class project and the Palatial Paintball Palace of Purging. Look it has to be posh, don't you see the statuary and the classy fountains?
And finally, be nice to the people that you hole up with. The most terrifying parts of the film weren't the random thugs or gangs of murderers, the domestic moments were much, much more disturbing.