A decade after its theatrical run, Martin Scorsese’s Shutter Island remains one of his most maligned and misunderstood works. It’s more than time for a re-appraisal and re-evaluation of a film that remains so very undervalued and underrated.

The film, based on a novel by Mystic River scribe Dennis Lehane, sees Leonardo DiCaprio play US Marshal Teddy Daniels who, along with his partner Chuck (Mark Ruffalo), investigates a missing inmate of a mental hospital on the eponymous Massachusetts island.

Daniels is haunted by his past, his time fighting in World War II and the loss of his wife Dolores (Michelle Williams), supposedly at the hands of a mysterious man called Laeddis (Elias Koteas) – images of which seem to intensify during his time on the island.

From the moment the pair arrive at the hospital, something feels off, and as the investigation gets deeper, Daniels becomes more and more convinced something much darker is going on. The film keeps giving us what may or may not be clues, and what are clues may have meaning beyond what it first seems.

“Why are you all wet, baby?”

When it premiered in February 2010, Shutter Island proved too hard a pill for some to swallow. Dissidents decried it as weird and confusing, the Scorsese faithful complained it did not have the true-world grittiness of his past work. (Curiously, criticisms not made against his next film, Hugo, which is about as fantastical as it’s possible to be.)

Shutter Island is a purposefully complex film from a filmmaker constantly experimenting. Scorsese’s reputation with making gangster films is unwarranted. His is a wide and varied filmography which has seen critical and commercial success outside of the crime genre, such as with The King of Comedy, The Aviator and The Last Temptation of Christ.

Shutter Island, then, is not a deviation for Scorsese, but another new territory for him to explore, and to throw his audience into.

“This Place Makes Me Wonder”

What makes the film what it is, and may have passed by many who dismissed it, is that, unlike other entries in the Scorsese canon, this film has no real application outside of itself. It has no real-world allusions such as cautionary tales from recent history Goodfellas and Raging Bull. There are also no allusions to other films like those in Taxi Driver or The Departed. It is an entirely self-contained story, everything that it is you can see on screen.

Every shot is intricately designed, every line of dialogue is meticulously crafted to help shape the distorted and mysterious tone and keep you, like Daniels, trying to uncover the biggest truths at the heart of the story.

The film is so well made beyond its construction. Robert Richardson’s photography in particular is gorgeous and mysterious, striking the perfect balance of colours and light for the tone of the film.

Many loved to point out the continuity errors seen in Shutter Island, but Scorsese’s attention to detail and care for his work makes it questionable why so many slipped through.

A more likely answer is these errors are deliberate to create a feeling of unease and distortion. This also goes for one key decision by Scorsese and music supervisor Robbie Robertson. They forwent a traditional score in favour of a ensemble of existing classical music, adding to the film’s patchwork feel.

The feeling that this has been assembled rather than grown organically brings out much greater feeling of the film and ties in with its major themes so well. No decision about what we see in Shutter Island has been made lightly.

“I’m Bones in a Box”

As always, Scorsese effortlessly gets the best performances from his cast, which, as well as DiCaprio and Ruffalo, also includes Ben Kingsley and Max Von Sydow. The highlight, though, is Michelle Williams as Dolores, who appears in flashbacks and as an apparition throughout the film.

Dolores is the emotional heart of Shutter Island. Whenever she is on screen, William’s heart-melting performance brings proceedings back to its human elements – loss, pain and the fight for life and the truth in a desperate situation. These can resonate with anyone, but in our hero’s case, it’s prescient on multiple levels.

Possibly one of the biggest barriers the film’s audiences found themselves facing was that it exists between genres. It begins as a film noir, then morphs into a psychological drama, while also branching into horror. It’s not in search of a definite genre, though, it is more than comfortable sitting in every one it wishes to explore. What’s more, it balances its many different elements expertly.

All this, of course, builds to the moment when the secrets are revealed, another site of contention between audiences. Whether or not you agree or disagree with how the film resolves itself, it cannot be denied that it sucks you in and keeps you hooked to the end. What other film can hold the attention of viewers it has long lost?

Ten years on, other films by both Scorsese and DiCaprio have seen more recognition than Shutter Island. (The Wolf of Wall Street, The Revenant, Inception) That it has been overshadowed does not mean it is not worthy of the same attention. Everything the film gets right – atmosphere, mood, mystery, craft, themes of identity and loss – are still intact and still work today.

Shutter Island has so much going for it that it doesn’t deserve to go forgotten. On its tenth anniversary it is time to take another boat ride back to this piece of pure entertainment masked as a near-art house, atmospheric period film – or take the trip for the first time for those who missed it first time.