Clint Eastwood’s latest military drama documents the true story of Navy SEAL Chris Kyle, reported to be the deadliest sniper in US history. A committed performance from Bradley Cooper anchors the film, which looks at Kyle’s life during war and peace time, but the end result has proved incredibly divisive and occasionally troubling.

Between 2002 and his honourable discharge in 2009, Texas-born Navy SEAL Chris Kyle served four tours of duty in Iraq as a sniper, during which time he claims to have killed more than 250 people. 160 of these kills are confirmed by the Pentagon (as at least one witness is required for confirmation). As portrayed by Bradley Cooper, Kyle is an all-American southern boy, raised to be a hunter and a “sheep dog” by his father, in order to protect the “sheep” from the “wolves” of this world.

When the US embassies in Dar es Salaam and Nairobi were bombed simultaneously in 1998, Kyle feels compelled to abandon his current job as a rodeo cowboy and join the Navy. He goes on to join the Navy SEALs and becomes a sniper. After the attacks of 11 September 2001, Kyle is deployed to Iraq, leaving behind his young wife Taya (Sienna Miller).

Kyle soon earns the admiration of the troops and is nicknamed “Legend” for his marksmanship prowess. He becomes increasingly distant on his infrequent trips home, and is steadily overwhelmed by his duty to protect “the boys” and “kill bad guys”.

Eastwood directs American Sniper with measured composure, never allowing the politics of the Iraqi invasion and occupation to dominate. The film never attempts to discuss whether or not the conflict was justified, but instead focuses on a story of individual heroism and doing one’s patriotic duty. While that is a perfectly reasonable approach to a war film, Eastwood’s handling of his specific subject leaves something to be desired.

In American Sniper, Cooper portrays Kyle as a wholesome man with an excellent skill set who is steadily overwhelmed by PTSD. The true story of Chris Kyle, as has been widely reported, is of a man drawn to violence, who relished his position wherein he could indulge and execute his desire without fear of reprisal.

Much has been made of the fact that Jason Hall’s screenplay is based on the bestselling memoir penned by Kyle about his experiences. Since its publication a number of events described therein have been questioned, challenged and even removed. Other events Kyle spoke of that allegedly took place after his return to the US – killing two would-be carjackers, shooting more than 30 looters in New Orleans after Katrina – have since been disproved.

While Kyle was no doubt an accomplished soldier, expert sniper and devoted patriot, he was also a pathological liar with a thirst for violence and killing. Hall and Eastwood choose to leave out these elements in the version of Kyle they present us with in American Sniper. While Cooper does his damnedest to convey the dead-eyed detachment that overcame Kyle during and after his four tours, on film this is seen merely as an after-effect of serving in the war, rather than an awakening or indulgence of anything that was within him all along.

American Sniper has been incredibly well received in the US, attracting large audiences and rapturous applause from fans in both blue and red states. Clearly Kyle’s story – or at least Eastwood’s version of it – has struck a chord with people. This is somewhat surprising as films about the Iraq war have not generally done well. Even the Oscar-winning The Hurt Locker failed to find an audience, although Kathryn Bigelow’s follow-up, Zero Dark Thirty, was better received. Perhaps enough time has passed since the conflict itself for audiences to gain the appropriate perspective. Also, as previously mentioned, the film wisely replaces politics with patriotism.

As a war film, however, American Sniper is nothing particularly special. Kyle’s training and initiation into the SEALs is dramatised to include Cooper, and fails to pack the punch of authenticity (or nauseating jingoism) that real-life footage of the same hazing in the opening of Peter Berg’s Lone Survivor managed. While that particular film went out of its way to shove politics to the front lines of another personal combat story, Berg’s film had the sole saving grace of some competently handled action sequences. Perhaps most surprising is that the numerous scenes of combat in American Sniper are rather dull and uninspired.

Eastwood has proved on countless occasions (Heartbreak Ridge and Letters from Iwo Jima to name just two) that he can direct exciting films focused on war and the military. Not to mention the number of action sequences he has staged in the countless westerns and thrillers he has helmed over the years. However, here they just fall flat. Save for a sequence late-on, in which Kyle and his team are forced to evacuate during a blinding sandstorm, there is precious little tension, drama or excitement to be wrung from these frontline encounters.

In an earlier incarnation of this project, Steven Spielberg had been set to direct, and the script was rewritten to flesh-out the role of Mustafa (Sammy Sheik) – a Syrian marksman, who had apparently competed in the Olympics, and was now fighting for the Iraqis. Spielberg had hoped to develop a rivalry between the two characters, both to heighten the drama and present a more balanced perspective on the war, but Eastwood it seems, was less inclined to pursue this route. While it may seem surprising that the man who went so far as to make an entire film in Japanese just so he could present the conflict in 2006’s Flags of our Fathers from the opposing side too, Eastwood wanted to tell Kyle’s story alone, and so Mustafa is relegated to faceless villain status.

But even as a character drama, American Sniper also falls short. As mentioned earlier, Cooper gives a strong performance that certainly proves he is an actor of ever-increasing range. But Kyle is an almost impossible man to read, let alone care for or sympathise with. Sienna Miller does solid work as his long-suffering partner Taya, but her role remains a one-dimensional “wife” throughout, begging him to come home safe, lay down his arms and protect his family, rather than the whole world.

Audiences should be aware of the fate that befell Kyle in 2013, while helping to rehabilitate other veterans struggling with post-traumatic stress. Had American Sniper truly wanted to honour the man’s memory, surely more of the film’s running time should have been spent on the lead-up to his death, and at least dramatised what is reported to have happened, rather than merely mention it in text over a black screen before cutting to documentary footage of the mourners lining the highways near his home. Admittedly the film was already in development when Kyle was murdered, but there was still plenty of time to explore his untimely death in its story had they wanted to. Instead, the film is very much one about a man at war, and should be judged on those terms.

As such a film, American Sniper is far from Eastwood’s best work, and an underwhelming addition to the genre as a whole. It neither explores the detrimental effects of PTSD in any meaningful way, nor tells us anything new about the conflict itself that we did not already know. American Sniper follows a patriotic man with a taste for killing who found a way to do both and be proclaimed a hero for it. Did he save American lives in the process? Absolutely. Should he be decorated for it? The US Navy certainly thought so, as Kyle received two silver stars and five bronze stars for his efforts. But as an accurate retelling of the man’s life or a thrilling piece of entertainment, American Sniper is way off target.