Dir Ridley Scott. US 2001. 148mins.

Although visually awesome in its gritty, ultra-realistic portrait of men in combat, Ridley Scott's Black Hawk Down highlights what's wrong with most Hollywood pictures even when they're superbly realised. Too many films suffer from a lack of coherent narrative and an absence of emotionally engaging or distinguishable characters to anchor a story, whether it's simple or more complex.

Admittedly, it was a near impossible task for screenwriters Ken Nolan and Steve Zaillian to adapt journalist Mark Bowden's personal account of the failed military action in Mogadishu, Somalia in 1993. Recounting how 18 Americans died, Bowden basically says that war is a messy, senseless act, particularly when it concerns a foreign country of which Americans soldiers knew little.

Playing his second consecutive military role this year (after Pearl Harbor), Josh Hartnett is nominally the film's star, but the script falters in establishing him as a distinctive hero by not separating him from the other soldiers. Clearly, Black Hawk Down is not the picture which will catapult the handsome and talented Hartnett into a major box-office draw, much to Columbia's chagrin.

Still, the studio has high hopes for its nerve-wracking war feature, which should enjoy a strong opening weekend. However, what producer Jerry Bruckheimer and Revolution head Joe Roth underestimate is the lukewarm word-of-mouth that their film will generate, due to its relentless, emotionally exhausting nature. For at least half of the film's excessive running time of 148 minutes, the audience are placed in the midst of chaotic, deafening warfare! That the film contains no home-front or civilian scenes, nor female roles, also presents further commercial problems.

Black Hawk Down owes its entire existence to Saving Private Ryan, Spielberg's 1998 masterpiece. The affinity between Spielberg's work and the new film is not accidental: producer Lustig also supervised Schindler's List, for which screenwriter Steven Zaillian won an Oscar. Shot through Janusz Kaminsky's piercing camera, the first 23 minutes of Spielberg's WWII epic presented the most revelatory battle ever recorded on-screen, a breathtakingly graphic portrayal of the violent combat at Omaha Beach on D- Day.

As far as the war film genre and its conventions are concerned, Scott's work here pushes the envelope even further, easily surpassing such recent conventional features as Enemy At The Gates, in which the 1942-3 siege of Stalingrad was reduced to a two-character cat-and-mouse game, or even HBO's acclaimed TV series, Band Of Brothers.

However, Black Hawk Down also shows the limits of visceral and sensory cinema in that it is based on a thin premise and asks the audience to sit through a gruelling experience without knowing much about the politics of this particular region. That this vital information is conveyed by title cards at the beginning and end of the story further confirms the screenwriters' muddled effort to construct individual characters, ones who are far more interestingly and fully realised in Bowden's well-researched book.

Less than a year after President Clinton assumed office he had to make a quick decision regarding Somalia, an East African country that, like Vietnam decades earlier, American intelligence knew little about. In October 1993, a band of elite American soldiers were sent to its capital Mogadishu as part of a UN peacekeeping operation. At first, the mission, which centred on abducting two top lieutenants of Somalian warlord Mohamed Farrah Aidid, sounded simple and manageable. There was no doubt that the effort was "well-intentioned" and even humanistic, for the US saw the mission as an integral part of its strategy to quell the civil war and horrendous famine that was ravaging the country.

In the first reel, the screenwriters establish with broad strokes some basic characters, the most prominent of who is Staff Sgt. Matt Eversmann (Hartnett), an idealistic young Ranger who is very much in the manner of Tom Hanks' hero in Saving Private Ryan. Almost positioned on the other pole of the spectrum is Ranger Spec Grimes (McGregor), a likeable desk jockey whose main job is as a crack coffee brewer. Other fighters include Ranger Lt Col Danny McKnight (Sizemore), a tough, cool-under-fire soldier; and Sgt. First Class "Hoot" Gibson (Bana), a Delta soldier who is a legend even to his comrades in the elite Special Forces. We quickly learn that the young Rangers and veteran Delta Force soldiers fight side by side against overwhelming odds, although no tensions exist between the two units.

Once in Somalia, the US troops become increasingly mired in the incomprehensible, senseless and feudal politics of a region torn by centuries-long battles between one clan and the other. For the duration of 18 long and harrowing hours, the soldiers remain trapped and wounded in the most hostile district of Mogadishu until a rescue convoy is mounted to retrieve them. Outnumbered and surrounded by an unknown, mass enemy, conflicts begin to flare within the group, dear friends lose their lives and new alliances are formed. In short, the soldiers learn the true nature of war, heroism and manhood.

The combat was considered by some experts as the US military's single biggest firelight since Vietnam, although that may change after Afghanistan. Almost by necessity, the battle is depicted as a step-by-step, minute-by-minute battle on the ground, in the air and at Joint Operations Centre, where Maj Gen William F. Garrison (Shepard), a two-star commander, who observes the action.

Unlike Saving Private Ryan, in which the band was small and comprised of soldiers who were easily distinguishable in terms of their physique, motivation and personality, the cast of Black Hawk Down is larger and its men more anonymous and interchangeable. Since not much is known about each individual before he goes into combat, it is hard to understand - and feel for - the transformation that he undergoes. Aspiring to be a combat chronicle at once epic and intimate, Black Hawk Down succeeds as the former but fails as the latter.

Much of the story is experienced through the eyes of Eversmann, whose mettle is sorely tested when he is unexpectedly handed command of one of the four "chalks" (units of men) assigned to secure the target building. Ranger Grimes also has some revelatory, if ironic, experiences: his long-held desire for "adventure" is finally answered in the streets of Mogadishu, far away from the safety of his typewriter and desk. Moments of relief from the relentlessly bloody combat are offered by Maj Gen Garrison, who watches helplessly as two Black Hawk combat helicopters go down in flames (hence the title) and the mission takes on painfully unexpected dimensions.

In addition to narrative and dramatic issues, Black Hawk Down also faces the political problems. The question is how to portray heroically a mission that was ultimately a fiasco where US soldiers died in a battle that many considered unnecessary and far from being well-planned' Since September 11 is likely to change US foreign policy, as well as our reaction to war features, it's indicative that two title cards were inserted at the end of the saga. One claims that the US learned a lesson about engaging in foreign conflicts, the other states that, under certain conditions, the US should still get involved in the politics of foreign territories.

With three back-to-back featu