There is a fine line between grotesque and high art when dealing with exploding heads and blood-splattered walls. Few directors today are able to walk that line with the macabre hilarity that Martin McDonagh does. You might expect “Seven Psychopaths” to be especially concerned with its own hilarity, given the number of psychopaths running around, but there is an impressive amount of sincerity and concern about the violence going on around the characters.

Colin Farrell is working with McDonagh again following their collaboration in 2008’s “In Bruges.” Farrell’s character is essentially McDonagh, an Irish screenwriter named Marty in Los Angeles struggling with writer’s block and alcoholism. All he has is a title, “Seven Psychopaths,” and a best friend, Billy (Sam Rockwell), determined to help him.

Billy and Hans (Christopher Walken) run a lucrative dognapping business, but when they dognap the wrong Shih Tzu, the dog’s owner, a gangster named Charlie (Woody Harrelson), comes after them. Marty finds out that psychopaths are even more of a pain to deal with than to write about.

Psychopaths aren’t all heartless, though. Billy is the driving force in the movie, and all his crazy stunts are done to give Marty something good to write about. At the end, this becomes a source of conflict as the story Marty is writing becomes the story of what is happening to Billy, Hans and him, and they all disagree on how it should end.

Earlier in the movie, Billy takes out an advertisement for psychopaths to tell their stories to Marty. At times, the large number of psychopaths becomes confusing as various side plots include an Amish psychopath, a Vietnamese psychopath and a rabbit-carrying psychopath, played brilliantly by musician Tom Waits.

Though the movie can be perplexing due to its nature of having nested stories within a story, “Seven Psychopaths” is never boring due to the well-written dialogue, marvelous acting and abundance of gunshots. Walken delivers his usual deadpan craziness, Rockwell slowly reveals himself to be a psycho and Harrelson delivers a heartbreaking portrayal of a concerned dog owner. Through it all, Farrell scrunches his eyebrows and is shocked by the goings-on around him. Hopefully for his sake, this is the 2012 movie people remember him for instead of “Total Recall.”

The movie is extremely violent and blood-splattered, but it never descends into gratuitous violence. McDonagh handles the violence at times in a tongue-in-cheek manner, but the characters’ reflections in the last third of the movie give it astonishing depth. He’s absolutely a director to keep an eye on. To say any more about the plot would be to give away some of the surprise, so suffice it to say that “Seven Psychopaths” is a dark comedy definitely worth your