Watching Waltz With Bashir is a singular experience, if only because it is comes in the unusual form of a fully animated documentary: personally I cannot remember seeing anything like it, and in this respect I found myself challenging many of the assumptions I had about the documentary format, and for the better. But there is more to the film than just this; lauded at Cannes earlier in the year, and rumoured to have just missed out on the Palme D’Or, this is a bold, powerful, well-constructed piece of cinema which should be required viewing for anyone interested in the troubled history of the Middle East.

Director Ari Folman is a veteran documentary filmmaker, but in his younger days he was a soldier in the Israeli Defence Forces. The film opens in a bar, where a friend is telling him of a vivid dream he has been having, relating to their shared days in army service. Folman is troubled, as he cannot remember anything from that period, in particular the events of September 1982 which led to the Sabra and Shatila massacre, a notorious event in the Lebanese Civil War in which the inaction (and probable complicity) of the IDF allowed Christian Phalangist militiamen to slaughter thousands of Palestinian refugees in West Beirut.

This inability to recall the events of that fateful day, excepting one strange vision of himself emerging from the sea beneath the light of flares in the sky, sets the thrust of the film’s narrative; Folman sets about interviewing former IDF comrades of his in order to fill in the blanks as well as to decipher his strange vision. But along the way, the journey of discovery becomes about other things: themes emerge including the loss of innocence, notions of personal and political responsibility, as well as the fragile, ever-changing nature of memory itself. For a film which relies so much on the memories of others to be so questioning of their inherent ability accurately to render the past is challenging in itself.

Where the film becomes challenging is how it uses its animated format. A more traditional documentary approach to tackling this subject would use a combination of present-day talking heads, found footage and reconstructions, with the lines between these fairly obvious to the viewer. But in choosing to animate not just the more illustrative segments but also the interviews, we are challenged to question the whole artifice of the documentary format, as well as creating a more homogeneous feel to the whole film. While the talking heads segments are the least visually exciting sections, they are well-paced, and the quiet, domestic surrounds of the interviews – spacious living rooms, sometimes with young children present in the background – come as a poignant contrast to the horrors of Beirut being described.

The tone of the film shifts between the relative calm of these present day interviewees, and the confusing, sometimes insane situations the young men in the IDF found themselves in in Lebanon. In a series of wry, blackly-comic scenes, both Israelis and Lebanese soldiers and civilians meet grisly deaths, accompanied in the score by some cheesy 1980s rock music. In one inspired moment, a soldier brandishing a machine gun begins to strum it along to the accompanying guitar riff – draw your own conclusions about the meaning. The strangely aloof, almost slapstick tone immediately recalls Apocalypse Now (1979) and a host of other ‘insanity of war’ films, Coppola’s masterpiece references more directly in a later scene where a news reporter fearlessly strides Kilgore-style into a hail of bullets, seemingly in the divine knowledge none will hit him.

The style of animation on show here is sort of a halfway house between the rotoscoped semi-realism of Richard Linklater’s Waking Life (2001) and the blocky impressionistic shapes of this year’s other animated arthouse hit, Persepolis (2007), though apeing neither – there is a feel to the film which is hugely distinctive. Amidst these more obvious comparisons, there is a discernable tonal similarity to Isao Takahata’s classic animated war film Grave of the Fireflies (1988), another powerful film about loss of innocence in wartime. What animating such horrors loses in terms of adherence to factual realism, it brings much in terms of communicating one man’s truth.

Director Folman is a veteran documentary filmmaker, which is made clear by his expert handling of the format here: a tight rein is kept on narrative, making sure that asides and digressions do not distract overly from the thrust of the piece. In a similar way to Steve McQueen’s Hunger (2008), there is no great political flag-waving, aside from one harsh condemnation of the murderous inaction of Ariel Sharon; otherwise, we are seeing just one man’s haunted rediscovery of his role in one of the Middle East’s most bloody events, and his probable equation of this to his parents’ horrific experiences in the Nazi death camps.

The film ends with found footage of the aftermath of the massacre, which I found almost unbearable in terms of its horror and magnitude. Some have criticized its insertion, but for me it is essential to balance the film: for so much of the duration it is a meditation on the fragility of memory, particularly of such horrific circumstances; but in considering this, we ourselves must not be allowed to forget the past.