Few movies offer the punch in the face experience William Friedkin’s Killer Joe offers. Pulizer Prize Winner Tracy Letts (August Osage County) adapted his own play here, his second collaboration with Friedkin after 2006’s claustrophobic and unnerving Bug.

Killer Joe is daring & high energy, asking its actors to start act one scene one at full throttle. Subtitled a Twisted Redneck Trailer Park Murder story, Killer Joe is assaultive and jarring from its opening shots. Rain in the movies is a often metaphor for rebirth, cleansing. Here it pisses down as heavy as curtains drawn at the opening of hell. There’s a huge barking dog and a man (Emile Hirsch) we’ll meet as Chris, running through the mud, screaming and banging on a trailer to awaken his waifish sister Dottie, (English born Juno Temple) sleeping soundly and cuddling with a snow globe. When the door finally does open for a pitiable Chris, its by his dad’s gal-pal Sharla (Gina Gershon) who gets one of the greatest, most distinctive character introductions in movies. On my list, its a close tie with Alice Krige’s first appearance as the Borg Queen in Star Trek First Contact. Um, wow.

Chris is running in a panic because he’s in debt to, obviously, the Wrong People and he has a money scheme he needs to run by his father, Ansel (a laconic and funny Thomas Haden Church). Its a plan that makes total sense if all you do is deal and take drugs in a trailer park. His plan is to murder his mother (“She ain’t doing anybody any good.”) and collect her insurance money. Whoever said two heads are better than one probably didn’t live in a Texas trailer. The two hire police detective turned part time hitman, Joe Cooper to do the hit on momma. They expect to pay Joe after the dirty work is done. Of course, they can’t be trusted. But instead of smartly walking away, Joe decides to take Chris’ sister Dottie as a retainer until the insurance check is cashed.

Dottie’s first appearance is hallucinatory and weird. Is she alright? How did she get here? She seems to’ve wandered in from another movie. She appears angelic, otherworldly, fragile as a porcelain tea cup. She materializes standing in the rain in a sheer negligee and is introduced as being a virgin by her icky brother, Chris.

But its Matthew McConaughey, baring shark blue eyes that hurt, who drop-kicks the film into the stratosphere once his title character Joe Cooper saunters through the door. This film is McConaughey’s turning point and what made audiences and critics re-examine his work. With this performance he doesn’t shed as much burn his romantic comedy roles in the past. Dressed in predatory black from his Stetson to his shiny gloves, he oozes psychopath, remaining polite, yet murderous. He’s too confident and too quiet. His eyes are always scanning, evaluating, thinking. Everyone is subordinate to him. He’s fearless.

The film is brilliant and unnerving—funny and perverted. But mostly daring. The poetic monologues and inventive conversations make it sound at times like a play. But Friedkin keeps it from looking staged or feeling too claustrophobic. Rather, Killer Joe leaves you kinda punch drunk and stunned. It well earned its NC-17 rating, with its violence front and center frame.

I’m close to calling this deeply misogynistic, but truthfully it doesn’t have much more–if any– respect for its male characters. Ansel as written is useless and cowardly, yet pitifully funny. Emile’s Chris leaves a trail of slime whenever he’s on-screen. Joe is obviously the smartest and most dangerous man in the room, as trustworthy as a cobra in your pocket. We as audience never get a clear read on him, unless you consider his conversations with Dottie. Its with her he reveals a slightly different man, even if he’s still acts a demon trying his hand at being human. We watch his behavior like we’re waiting for a shark to jump from still water. When he does let go into full psycho mode during a kitchen interrogation, the violence that emerges is awful and hysterical. Letts as a writer keeps upping the ante, challenging himself to write crazy and push boldly into the unknown and unexpected. He stubbornly refuses any obvious or easy choices for his characters. And that push against expectation gives the film its edge. Its funny and nasty and alive in ways that stage adaptations, hell even original movies, often miss.

Two things. First, Killer Joe has one of the most potent and hysterical WTF musical cues I’ve ever heard. Friedkin needle drops on a song even Tarantino might struggle using in a equally funny and absurd context. Second—older movie trailers used to warn audiences: “Nothing can prepare you for the ending of…” Even after repeat viewings and some stiff drinks, nothing will prepare you for Killer Joe’s final act. Listen for the gorgeously laced dialogue and then think on the actors who’ve taken this on as a stage play and performed it live, five nights a week and twice on Saturday. That thought is as startling to me as the movie itself.