Spoilers for Shutter Island ahead.

From the trailer and poster of Shutter Island, a viewer would be forgiven for ᴀssuming the movie is scary. However, Martin Scorsese’s 21st-directed narrative feature movie is a much harder film to categorize than it may appear on the surface. This 2010 film is of a different flavor than any of Scorsese’s other films, perhaps closer in line with Taxi Driver than anything else and certainly a far cry from any of the director’s 21st-century movies. Shutter Island stars Leonardo DiCaprio, Mark Ruffalo, Ben Kingsley, and Michelle Williams in its ensemble cast.

Shutter Island is based on the book of the same name by Dennis Lehane, and for the most part, adheres to the story. It follows U.S. Marshal Edward “Teddy” Daniels (DiCaprio) and his new partner, Chuck Aule (Ruffalo), who are investigating a case at Ashecliffe Hospital for the Criminally Insane, which is located on the remote Shutter Island off the coast of Mᴀssachusetts. From the outset of the film, something is clearly wrong, and Scorsese reels in the audience with a rewatchable, twisting film that doesn’t fit neatly into one genre.

Shutter Island Is A Neo-Noir Psychological Thriller Rather Than A Straight Horror

The Film makes Viewers Want To Explore More Of The Island

While many of the images, including the cover art, from Shutter Island suggest the movie is a straight horror film, it’s much more of a psychological thriller, with some horror adjacent moments. There are few actually frightening moments, and even the jump scares are quickly dissipated and forgotten about. What Shutter Island is filled with is a creeping sense of doom that surrounds the whole movie. It’s not dread exactly and instead makes for a film that the audience wants to spend more time in.

The Island of Doctor Moreau by H. G. Wells is an apt comparison. Both the book and its adaptations are frightening for their stories. However, there’s also something enchanting about the island that draws a reader or viewer in. People may be turned into animals in horrific procedures, but the reader wants to know exactly how and is curious as to why this is happening. It’s the same for Teddy and Shutter Island. The events happening there are ostensibly frightening, but they are even more thought-provoking and tantalizing, a mystery waiting to be unshrouded.

Shutter Island is at its core a neo-noir thriller movie, and it follows the tropes and visual styles of 1940s and 1950s American film noir. The lead is an inscrutable detective, and the mystery seems to involve him the further he digs into it. Violence in neo-noir movies is rare, but when it does happen, it’s often shockingly bloody and gruesome. The World War 2 sequences toward the end of Shutter Island primarily provide these shocking moments, as do Teddy’s dreams. The psychological ramifications of Teddy’s discovery form the thrills in Shutter Island, not the scares.

Shutter Island Is Still Very Scary Despite Being More Of A Thriller

The Sinister Atmosphere Creates Unnerving Tension

Though the scares don’t define Shutter Island, there are still plenty of them throughout the film. The setting itself is distressing with dark clouds and constant rain covering the island, creating a gloomy and angry atmosphere that builds tension throughout the film. As Teddy explores Ashecliffe Hospital, the cramped quarters and oddly behaving orderlies create a claustrophobic and nightmarish feeling. This is combined with the actual nightmares Teddy has, often of ᴅᴇᴀᴅ children and people.

While these are disturbing images on their own, the fact they almost all go unexplained makes everything feel a touch more sinister. A sneering inmate is more frightening because she seems to have an inside joke that Teddy and the audience are not privy to. A nervous guard is more frightening because, ostensibly, they are supposed to be on Teddy’s side. As Teddy finds himself uncovering the strange mystery at the heart of Shutter Island, the film gains an intense momentum that’s enough to make a viewer’s hair stand up on end.

This sense of doom that permeates the film makes the minor jump scares feel all the more sudden, and therefore more effective. A guard coming around a corner, a door banging open, a thought-ᴅᴇᴀᴅ girl suddenly opening her eyes; the horror of these moments is elevated because the audience is already on the edge of their seat. This is put to most effective use in the biggest jump scare of the movie when a patient jumps out at Teddy and Chuck as they explore the mysterious Ward C. It may not be horror, but Shutter Island can still frighten.

Martin Scorsese’s Mystery Film Plays With Horror And Thriller Conventions

Shutter Island Flips Noir Tropes On Their Heads

Shutter Island is a twisty thriller that needs to be watched more than once to be fully appreciated. It’s an unusual film, not just in Scorsese’s oeuvre, but in the canons of neo-noir and psychological thriller films. There are parts of Shutter Island that are wholly conventional, but whenever he can, Scorses flips the script on these conventions. In a traditional neo-noir movie, the protagonist would likely behave the same way as Teddy. He’s a classic archetype, a man beset by regrets, trying to find the truth, and targeted by an unjust and uncaring world.

However, the opposite is true in Shutter Island. Teddy is trying his best to cover up the truth. He’s so insistent on covering up the truth that he’s concocted an elaborate backstory for himself to make him forget. Furthermore, Teddy isn’t trapped in an unjust and uncaring world. In fact, the dark and fearful hospital he finds himself investigating appears to be a fairly progressive place of healing, willing to use all its resources to help Teddy understand what he’s going through. The horror and psychological grief Teddy experiences are of his own making.

Teddy isn’t a man being led slowly into a dark, evil pit to uncover what lies below. Instead, Shutter Island is about a group of people desperately trying to lure Teddy up the stairs and out of the pit he’s created for himself. They want him to be free; it’s only Teddy who refuses to rise. His decision at the end of Shutter Island isn’t just to stay in the pit, it’s to make sure he never knows there’s a way out again. A horrifying or tragic ending, depending on how the viewer looks at it.