Shutter Island was shuffled from an intended fall 2009 release date to February 2010, which changed its profile from Oscar-season prestige picture to a late-winter thriller with low expectations (a studio delaying a film is often a sign of a lack of confidence), but it has proven to be a sound business decision; though the film has met with generally positive reviews (62 on Metacritic, 67% freshness on Rotten Tomatoes), it nevertheless might have been regarded as a disappointment from Martin Scorsese and struggled to get traction during the crowded awards blitz. Now, the film is well on its way to a domestic gross of $100 million.

The irony of all this business of release schedules and box office receipts is that Shutter Island happens to be a great film, but will probably be remembered more as Scorsese’s genre piece than as a worthy addition to the director’s canon. A fair trade, I suppose. People are seeing it. A lot of them. That’s what matters.

But if it’s remembered as a mere potboiler, that truly would be a disservice. Emphasized in the advertising are spooks and scares and gotcha moments; it’s not a misleading characterization, per se, but it is a drastic oversimplification. The film has a richness of style, theme, and character that wouldn’t translate in ads — at least, not in the ads for a movie you’re trying to sell to a mass audience. Start to prattle on about metaphor, morality, and the nature of violence and you’ve lost them.

The film begins on a ferry carrying US Marshal Teddy Daniels (Leonardo DiCaprio) to Shutter Island off the coast of Massachusetts in 1954. The island is home to Ashecliff Hospital, a facility for the criminally insane, where patient Rachel Solando (Emily Mortimer) has disappeared without a trace.

Scorsese draws us into his vivid world immediately. We’re treated to a foreboding wide shot of the island followed by a closer, deep-focus image as the ferry approaches the dock. As Teddy and his new partner Chuck Aule (Mark Ruffalo) enter the hospital’s gates, the suspense is punched up by music that sounds like an action climax when we’ve barely begun the introduction, but that’s the only stylistic flaw I can think of.

The film is just about perfect as an evocation of atmosphere and suspense. Scorsese demonstrates impeccable technique, a triumph of style furthering substance. The cinematography by Robert Richardson uses high contrast in interior scenes, shining bright, glaring lights on his characters amidst dark settings that are full of great detail; the production designer is Dante Ferretti, in whose last film, Sweeney Todd, he also made a fully enveloping world to reflect a lead character’s deteriorating psyche. Visually, the film is madness made manifest, an illusory world of broken minds and unspeakable acts.

Longtime Scorsese collaborator Thelma Schoonmaker’s editing evokes memories, first in tantalizing flashes of images yet to be understood, then in longer, exquisitely paced stretches where the bits and pieces begin to assemble themselves into mysterious dreams and hallucinations. Scorsese’s use of sound further enhances the effect; he knows precisely when to punctuate a scene with music or silence, and consider his use of striking matches as Teddy makes his way through a dangerous cell block — the aural snap and the bursts of light made me grip my chair a little tighter.

If Shutter Island were merely a mood piece, it would be good enough to recommend, but Laeta Kalogridis’s screenplay, based on a novel by Dennis Lehane, contains trenchant philosophical and psychological insights. The action is set not long after World War II; Teddy was a soldier who helped liberate Jews from the Dachau concentration camp. This is not simply backstory. What Teddy witnessed has changed him, and by extension changed us all. The island represents a primal reaction to the Holocaust, a schism of our fundamental understanding of the world. It overturned our beliefs of what mankind is capable of and left us floundering in a world of violence we cannot reconcile.

On Shutter Island, we find a mother capable of drowning her own children, a man who viciously murdered and disfigured his victim out of feelings of sexual inadequacy, and doctors who… what are they up to exactly? Are they performing grisly experiments? Creating sleeper agents? Are our institutions committing the same crimes committed by the Nazis? Paranoia overcomes us: How can any of us be innocent if any of us can be so terribly guilty?

The hospital warden, played in a brief but memorable performance by Ted Levine, is casually cynical. He believes violence is our nature, that when stripped of social order — law, religion, consequence — we would surely kill each other. Teddy vehemently disagrees, but he can’t be so sure anymore. The film closes on a line of dialogue I won’t reveal, but it’s a perfect summation of the film’s central conflict — not between Teddy and the hospital, but between our better selves and the demons we find within us.

Watch a trailer for the film here: