There's absolutely no shortage of revenge films in the world of cinema, but there's certainly a lack of films with narratives that slowly unravel throughout, especially alongside a question of morality and character.
Blue Ruin manages to introduce its protagonist as more of an antagonist. A man in complete ruin -- no pun intended there, honestly -- with no respect for people or the law. Whether he cares for his own well-being is a question that arises very shortly as we begin to witness the first slices of action within the film.
There's a certain arthouse feel to the filmmaking, the lack of story and context from the start, the directing that uses events to produce character development rather than heavy amounts of dialogue, the ruthlessness of our protagonist as he plays smart with his actions; a clear indication that this has been thought through.
As the film begins to unravel, it becomes clear that this is a tale of vengeance. It's a case of a man that has experienced wrong and is set to inflict pain and suffering in return, and as we begin to learn why, not all is told to us. We receive glimpses of a larger narrative at hand and we feel for the protagonist, wanting him to get that revenge. We begin to feel for him at every challenge he faces, and that begins to question morality. Whether what he's doing is going too far, or makes him the same as those who he's attempting to hurt back.
That said, it's done in a way where we continue to sympathise with the protagonist. We want that revenge as well as he does. We know it's wrong, but we see the fear he faces himself. The threat of whether he will be targeted next, or those he cares about. It becomes a 'survival of the fittest' game in which the possibility of him and those he cares about may die, or those who wronged him will die first. The opportunity to get revenge alongside that gives us a protagonist with no other options; this is something that's questioned during the film, as he asks whether there is another way that it could all end, preferably in peace. Though peace isn't what he wants, and he knows it. Peace comes after revenge.
Blue Ruin really pulls you along for the ride. It holds you in with a simplistic narrative that's slowly explored. It explores morality without telling you which option is right or wrong. It uses all it can to tell a story through multiple methods of filmmaking, and it does so in a way that's rarely seen in modern cinema.