There is a song by LOX and an artist/rapper (Eve) called Ride or Die chick. Well sometimes they use a different word and not chick, but I only mention it, because the title reminded me of the song ... and I reckon you could say it is fitting when it comes to the story.
Now this starts off quite intense ... sexy time (and nudity) and violence combined into something quite horrible - in a "good sense" I reckon. As in suspensful and making the movie interesting ... not to mention the characters. Then we get a flashback that explains why we are were we are ... and then the drama starts and unfolds. So while you may feel that the movie starts with a bang (no pun intended), it really does slow down.
So I reckon some might not like this because of the way it starts (squeamish people) and some will not like how it continues ... those who got sucked in by that really powerful beginning. And then there are those like me, who like the mixture of those two things. Slow moving mostly, it does not hold back its punches ... not for the faint hearted as you may already have recognized.