Stephen King’s “Gerald’s Game” is relentless. We’ve seen quite a few Stephen King adaptations this year, ranging from tragic (“The Dark Tower”) to solid but flawed (“It”). Netflix’s new adaptation of a King novel is something straight out of your worst nightmare.

Directed by Mike Flanagan, “Gerald’s Game” is an exercise in claustrophobia and anxiety, growing slowly till it hits a fever pitch. Part thriller, part commentary, part creature feature and all horror, “Gerald’s Game” is a very solid showing from Netflix’s growing horror collection.

Flanagan has been making a name for himself over the last few years, particularly within the realm of indie horror. After breaking through to the mainstream with his 2013 film “Oculus,” Flanagan went on to make “Hush,” an ingenious film about a deaf woman encountering a serial killer at her home, and the surprisingly spooky “Ouija: Origin of Evil,” a rare, quality sequel to a universally panned original. Over his last few films, Flanagan has established himself as a director who understands the conventions of horror – and how to break them. “Gerald’s Game” falls in that same category.

The film is set almost entirely in a single room, the master suite of the cabin where Jessie Burlingame (Carla Gugino) and her husband Gerald (Bruce Greenwood) have gone to rekindle their relationship. The two decide to try out some kinky role-playing with handcuffs to get things started, but things turn south when Gerald suffers a heart attack and falls on the floor, dead. Jessie, still handcuffed to the bed, is forced to find a way to survive while being tormented by dogs, her past and her dead husband. Chase scenes are replaced with anxious frustration, with that single room becoming a psychological and physical gauntlet of survival.

Like many other modern horror films, “Gerald’s Game” isn’t a typical horror film. No jump scares, string-focused or gruesome kills, though there is plenty of gore. Instead, the film is primarily a psychological horror film, not unlike “The Shining” or even “Get Out.”

Jessie’s past horrors come back to haunt her in surprising ways, and the majority of the film is set around a conversation with herself and her dead husband, both hallucinations after the stress causes her to ‘lose her mind.’ This style of horror lends itself well to Flanagan’s style, providing a deep dive into the character’s psyche instead of the stereotypical killer or creep. Both of the leads put in great performances, particularly Cugino in her remarkably human portrayal of Jessie.

Now, I started this review out by calling the film “relentless.” That might sound strange, especially since this is a horror film without any major set pieces or scares, but man is it terrifying as hell.

Terror is the linchpin of  “Gerald’s Game,” and it doesn’t let up. The film starts off on an odd, uncomfortable note and continues to ramp up from there. Once the film makes it to the bedroom, the brakes are cut. It just. Doesn’t. Stop. It’s not perfect and the beginning is a little slow to kick in, but that’s easily forgivable when looking at the rest of the work.

Details are revealed that flesh out the already interesting characters in equally interesting ways and before you know it, you’re watching a horror film where the main villain is sexual abuse. It can be a tough watch, but if you’re up for it, “Gerald’s Game” is totally worth it and you’ll be treated to one of the best ending twists of the year. 4/5