Based on Kim Barker's equally caustic and comic memoir of her experiences covering Operation Enduring Freedom, The Taliban Shuffle, Whiskey Tango Foxtrot explores the particular thrills and challenges encountered by a female war correspondent.

Directed by Glenn Ficarra and John Requa of I Love You, Phillip Morris, from a script by 30 Rock writer Robert Carlock, Tina Fey stars as the fictionalised Kim Baker (oddly sans 'r'), who ditches bland reportage, a failing relationship and daily humdrum in New York for military embedment in war-torn Afghanistan. Thrown determined but bewildered into the fray, Kim is schooled in the ways of wartime coverage and carousing by fellow female correspondent Tanya (Margot Robbie), taciturn General Hollanek (Billy Bob Thornton) and lewd freelance photojournalist Iain (Martin Freeman).

A perfect vehicle for Tina Fey's brand of sweetly self-deprecating but sharp humour - the New York Times review of the book even noted Barker as "a sort of Tina Fey character" - Whiskey Tango Foxtrot reveals her previously underutilised dramatic talent. The jokes can lean a little too heavily on Kim's fish-out-of-water floundering through military engagements and Afghani culture - with pratfalls to boot - but Fey's terrific performance ignites even the duds.

Despite the bare attention given to the travails of Afghani women, the feminist struggle at the heart of the film is pitched well. The film neither skates over the realities nor bashes the audience over the head with the discord. It's refreshing to see a comedy centred on a female depiction of defiant courage and flourishing confidence in a dangerous field. Whiskey Tango Foxtrot is at its best when focusing on the costs and gains of Kim's journey from clueless neophyte to intrepid war correspondent.

Less successful is the two-dimensional supporting cast. While Robbie manages to make the most of the one note of sass she's given to play, both Freeman and Thornton are saddled with insurmountably thin characters. Worse still is Alfred Molina's woefully broad performance in brownface as a slippery and lecherous Afghan minister - the film's lowest point.

Such sour moments become harder to disregard across an indulgent two-hour running time. Whiskey Tango Foxtrot scotches a slick pace in the first hour, wearing out its welcome towards a conventional climax. Beyond an interesting take on the disconnect between the investment required to understand the complexities the situation and the flighty considerations of news media, the film is unwilling to be incisive enough to justify such length.

Hollywood has been hesitant to produce comedies dealing with recent US invasions, so Whiskey Tango Foxtrot benefits from a fallow field. While it's far from the mordant wit of In the Loop, it feels fresh enough to limit the sting of such comparisons and deftly handles humour in a context of death and destruction. Too lightweight to have any effect on the discourse of war, it should spark some reappraisals of Fey's potential.