In his second movie, the Irish playwright Martin McDonagh has mangled together a comic, self-aware revenge flick that’s half Guy Ritchie, half Charlie Kaufman.

If that sounds like an awkward pairing, it is. “Seven Psychopaths” is manic and messy, and McDonagh doesn’t yet have the visual command for a sprawling, madcap tale as this.

But it’s also filled with deranged wit and unpredictable genre deconstruction that makes “Seven Psychopaths” if not quite a success, a fascinating mutt of a movie.

Colin Farrell plays Marty, a hard-drinking screenwriter in Los Angeles and a clear stand-in for McDonagh. He has his movie title — “Seven Psychopaths” — but little else.

His friend Billy (Sam Rockwell) is his sounding board. But as Marty tries to write, he gets sucked into Billy’s own hijinks. With the help of his older friend Hans (Christopher Walken), Billy kidnaps dogs and then returns them for the reward money. This practice gets them in trouble when they swipe the Shih Tzu of a dog-loving gangster (Woody Harrelson). Bloody bodies quickly accumulate.

That this is the plot isn’t necessarily clear until fairly well into “Seven Psychopaths.” At first, it’s paced by stylish introductions of various psychopaths.

It’s an excellent cast, but this is Rockwell’s movie. The actor has long specialized in loose cannons but this may be the most fun yet.

He enthusiastically supports Marty, trying to get him to write, while revealing that he, too, might be a fittingly unhinged character for the script.

In urging Marty’s script forward, Billy also pushes along “Seven Psychopaths.” His suggested cliched vision for Marty’s script (the psychopaths team up for a cemetery shootout) could easily be in theaters any given week. He is the excited advocate for gunplay, action and, absolutely, a big showdown finale.

Marty, though, wants his film to be about “love and peace” and halfway through “Seven Psychopaths,” he contemplates a sudden turn away from the expected plot mechanics.

Apoplectic, Billy responds: “What are we making, French movies now?”

For a while, this is exactly what “Seven Psychopaths” does and it’s when it finds its footing.

Also in the desert, Walken’s character — whose slow, deliberate enunciations are like a soothing metronome for film — takes peyote, which is worth the price of admission.

After breaking apart the crime film, McDonagh puts it back together again for a conclusion worthy of the genre. In the end, the movies — in all their insanity — win. The French lose.