The writer-director of “In Bruges,” playwright turned filmmaker Martin McDonagh, sells out and makes his first Hollywood film, “Seven Psychopaths,” a commentary on selling out.

Well, that and Hollywood’s obsession with psychopaths. And his own.

True to title, it’s about seven psychopaths and a screenwriter named Marty writing a movie about them.

But as a possibly psychopathic character tells the writer (Colin Farrell), “YOU’RE the one so fascinated by psychopaths. After a while they get tiresome, don’t you think?”

Like generations of great talents “going Hollywood” before him, McDonagh takes his shot at having it both ways. He hired a quartet of the coolest character actors in the business and revels in the presence of Farrell, Christopher Walken, Woody Harrelson and Sam Rockwell. He imitates and takes a blood-stained swipe at genre nerds such as Quentin Tarantino or Joe Carnahan, and their movie lover’s style of bloody-minded movie. He has characters comment on situations and scenarios as they “rewrite” scenes, endings and shootouts for the screenplay Martin is sure will be big at the box office.

And in case we’ve missed McDonagh’s bemused remove from all this, he makes Linda Ronstadt’s “Different Drum” the theme song of his writer-hero.

“But” — as that song goes — “don’t get me wrong, it’s not that I knock it,” because “Psychopaths” is profane, gruesome and hysterically over the top.

The sheer pleasure of watching Walken work with his disciples, Harrelson and Rockwell (maniacally mannered here), and watching McDonagh’s alter-ego, Farrell, in another McDonagh role worthy of his talents, is undeniable.

But after a while, even those pleasures wear thin.

Hans (Walken) and his buddy Billy (Rockwell) are running a little dognapping-for-reward-money scam so that Hans can care for his terminally ill wife. And they’ve nabbed the wrong dog, a Shih Tzu beloved by mobster Charlie (Harrelson), who is willing to kill to get that dog back.

Basically, as long as you remember that this is just a “Smokin’ Aces” for the literary-minded, you’ll be fine, and you’ll enjoy the performances of the actors.