Jeremy Saulnier's follow-up to his unflinchingly brutal revenge film "Blue Ruin" officially caps off the first third of this year's theatrical releases. For true film buffs, it is one last opportunity to savor a healthy slice of indie cinema before all those summer blockbusters roll into theaters. It also joins "10 Cloverfield Lane" and a few other thrillers as one of the best that the genre has seen this year so far. But unlike its recent predecessors, "Green Room" gets down to the genre's base elements, throwing any fluff that can be spared out the window. Saulnier brews a wickedly visceral intensity throughout, complete with solid acting, moody lighting and ultra-violent deaths that will make your skin crawl. All that's missing are characters we can truly sympathize with as they fight their way through the film's graphic bloodbath.

For the last gig on their tour, The Ain't Rights perform at a neo-Nazi skinhead bar in the woods outside Portland, Oregon. After the show, the punk band accidentally stumbles upon the murder of a young woman, forcing the white supremacists to take their visitors hostage in the green room. Not long after The Ain't Rights find themselves trapped with a loaded gun pointed at them, Darcy Banker (Patrick Stewart), the owner of the bar, is called upon to help his men deal with the situation. Blood is soon split as tensions escalate on both sides.

Saulnier begins on an appropriately quiet note, taking the time to establish the dynamics between the band members before they find themselves at the mercy of the racist skinheads. There is also a bit of clever foreshadowing during these first few minutes, including a brief moment where Pat (Anton Yelchin), the bassist, washes Sharpie markings (left by his bandmates as he slept the night before) off his face. The band's punk status is cemented as they facetiously perform a cover of the Dead Kennedys song, "Nazi Punks F**k Off." It's the only sequence of "enjoyable" tension before Saulnier really nails us into our seats.

The ensuing bloodshed as a result of distrust and deception on both sides is the stuff of nightmares. None of it feels arbitrary of looks flashy, but Saulnier (ahem) executes the violence in such a way that you'll probably be left with every single malevolent act of the film burned into your brain. It's as unrelenting as you might expect, but Saulnier's lack of focus on the individual motivations of his protagonists leaves us with no one to really root for. If anything, more attention is paid to Darcy (who is played marvelously by Stewart) and a few of his men, as we discover that even though they are more than willing to crack skulls, they want nothing more than for the whole thing to end quietly and without much casualty. But when push comes to shove, survival is all that matters for everyone involved in this twisted scenario.

Make no mistake, though; these are very human characters squaring off against each other. Saulnier has taken great care to make sure that we're not simply watching cookie-cutter good guys and bad guys maim and kill each other in horrible fashion. The performances also help drive this point home; Yelchin hits his marks fairly well, there is some interesting work from Imogen Poots as Amber, the murder victim's best friend, and Macon Blair is particularly good as Gabe, Darcy's right-hand man in the operation. All the same, without proper insight into each band member, there is little room to care much for Pat and his friends. Some of the tension feels a bit deflated because of this, but Saulnier's distinctive eye for the grim and the grisly make "Green Room" an effective exercise in razor-sharp intensity.