TELLURIDE — There are two reasons Andrew Hodges' biography of Alan Turing references "The Enigma" in its title. The first is in reference to the Engima machine, the legendary secret code the Nazis used during World War II, which was solved by a secret UK military division lead by Turing. The second is Turing himself. 

Known for his advancements in computer theory (look up Turing Machines), BBC News noted that Winston Churchill once referred to Turing as having made "the single biggest contribution to Allied victory in the war against Nazi Germany." Somehow he became a historical footnote until finally getting proper credit for his WWII accomplishments in the 1990s. Eventually he was pardoned for a "gross indecency" charge (which destroyed his life) by the Queen of England in 2013. He was a hero the Western world didn't know about for decades and in many ways the circumstances of his death and the secrecy of his personal life made him as much of an enigma as the code he broke. It's therefore disappointing that the new biopic "The Imitation Game" fails to do his life justice.

Directed by Morten Tyldum ("Headunters") from a screenplay by Graham Moore, "Imitation Game" weaves its narrative through pivotal moments in Turing's life, from his younger school years, his time at Hut-8 breaking the Enigma code and a 1952 break-in that led to his eventual prosecution for engaging in homosexual acts. Benedict Cumberbatch plays Turing for most of the film with a very talented Alex Lawther portraying him as a teenager.  

The movie fashions the adult Turing as a genius, but also as obsessive, socially awkward and self-involved. As you'd expect, Cumberbatch does a wonderful job bringing this characterization to life and it's often his performance that overcomes some of the film's melodramatic tendencies (Alexandre Desplat's fine score often helps to smooth out these bumpy spots as well). The "Sherlock" star also has the unique ability to create sympathy for a character who could come across as cold and callous in another actor's hands.

Those WWII years are the centerpiece of the movie, when Turing's anti-social problems reared their head at the worst possible time. Forced to work with other mathematicians and puzzle solvers recruited to break the code, Turing immediately decided he had no use for them. And those men, played primarily by Matthew Goode and "Downton Abbey's" Allen Leech, quickly learned to view his behavior towards them as condescending and disrespectful. It's not until Turing clandestinely recruits the charismatic Joan Clarke (Keira Knightley) to the team that they begin to truly collaborate as a working unit to break the Nazi code.

While it often plays less cinematically than the filmmakers intended, you could successfully argue this is the most compelling part of the film. It also helps that Turing and his colleagues have to wage their work against a distrustful Admiral (Charles Dance, partially channeling Tywin Lannister), an MI6 chief with dueling priorities (an effective Mark Strong as Stewart Menzies) and the ticking clock of a nation falling to a German invasion. Tyldum is able to successfully fashion dramatic tension from this storyline more than any other.

Another part of the film that is particularly successful is the depiction of a young Turing and his "romance" with fellow student Christopher Morcom (Jack Bannon). The aforementioned Lawther is so good here you wish the film spent more time depicting this particular relationship so it has more of an emotional impact for the audience.

Unfortunately, where "Imitation Game" ultimately falters is in tackling Turing's later years and subsequent demise. In some ways, this period is meant to bookend the film, but instead just leaves unanswered questions while diminishing actual historical events. The audience discovers Turing's choice of punishment for his gross indecency charge during an impromptu visit from a concerned Clarke, who's heard about it in the papers. It's the most disturbing, indecent and tragic part of Turing's final years and is spoken out loud just once. Tyldum and Moore must have thought revealing it in this context allowed them to bring Clarke back into the picture and give Cumberbatch an emotional breakdown "moment." Instead, the whole sequence comes across as both forced and, worse, safe. The film doesn't even reveal Turing's final fate until a flashcard that occurs over "happy memories" of him celebrating breaking the Enigma code with his colleagues.

To be honest, the more I ponder the ending of the film the more frustrated I become. In effect, much of Turing's gay life is completely washed over. He says he had numerous affairs/lovers, but the film pushes the central relationship between his one-time fiance Clarke as the most prominent. That's somewhat odd after Turing justifies the entire engagement as his way to keep her working on the secret project. Let's be clear, Turing was one of the greatest gay men of the 20th century whose life was destroyed by an archaic charge in 1952. It's almost head-scratching how the film could be structured to diminish this part of his life.

It's worth noting there have been two previous attempts at telling Turing's story, the 1996 TV movie "Breaking the Code" starring Derek Jacobi as Turing, and 2011's "Codebreaker," which received a limited theatrical release in the U.S. Many hoped, thanks to Cumberbatch's involvement, that "Imitation Game" might become the definitive film on this historical figure.   Unfortunately, that simply is not the case.

"The Imitation Game" opens in limited release on Nov. 21.