Although boasting a committed, frightening performance by Johnny Depp, Black Mass proves to be an underwhelming affair that takes a conventional approach to a fascinating true crime story.

Ever since Mystic River won Best Picture at the 2004 Oscars, the “Boston crime movie” has been a regular fixture, with the likes of The Departed, Gone Baby Gone and The Town following suit. Now comes Black Mass, a Scott Cooper directed film based on the exploits of notorious South Boston gangster James “Whitey” Bulger, who for decades was second only to Osama bin Laden on the FBI Most Wanted list.

Portraying Bulger is Johnny Depp, who with the aid of excellent hair and make-up delivers an imposing, frightening performance that reminds just how good Depp can be when the right part comes along. Yet unfortunately for Depp (and anyone campaigning on getting Depp that fourth Oscar nomination), Black Mass is too formulaic a film to warrant much in the way of high accolades, with its “been there, done that” structure of flashback, narration and gravely Boston accents, proving to be incredibly uninspiring.

It’s truly a shame. With his first two features (Crazy Heart and Out of the Furnace), Cooper was building towards “that film” poised to make him a household name. Black Mass had the elements yet Cooper plays it too safe. Rarely do the stakes at play feel urgent enough to warrant any kind of heavy investment, with this story of the “alliance” between Bulger and the FBI telemovie-of-the-week in quality, with facts presented yet no substance nor style invested.

This is especially felt in the FBI side of this devil’s deal, with Joel Edgerton in particular hamming it up as (now) disgraced FBI agent John Connolly, whose hero worship of Bulger led to the abuse of his position as protector of one brutal criminal enterprise in order to rid Boston of another (the Mafia.)

In the history of Boston character archetypes Edgerton’s Connolly is the loudest, with the combination of marbles in mouth Massachusetts accent, quaffed to the nines hair, and over the top arm flailing robbing his portrayal of Connolly of much needed depth. Not only is the character a weasel of the highest order, he is also an annoyance. In a year where Edgerton staked his claim as a strong creative force in The Gift, his performance in Black Mass almost derails his momentum. Almost.

On the flip side is Depp as Bulger. Depp has made a career of hiding under layers of make-up (Edward Scissorhands, Charlie and the Chocolate Factory), yet rare is the performance where Depp uses his disguises to enhance rather than distract. Black Mass offers that opportunity and Depp takes full advantage, delivering not only a scary good performance, but a genuinely scary one altogether that’s almost vampiric in presentation with the combination pale complexion, dark garb and chilling demeanour.

It’s a performance that suits the title Black Mass to a tee, yet is curiously misplaced in the film itself. Black Mass has gone through numerous rewrites and incarnations over the last several years. Somewhere during that time whatever soul, whatever depth, whatever personality that inspired Depp to go that extra mile has disappeared, resulting in a waste of a potentially great film.