Few who caught Joshua Oppenheimer's The Act of Killing – an oblique revisiting of atrocities in Indonesia – would disagree that it was one of 2013's very best films. What a pleasure it is to begin 2014 with one that feels a little like a worthy companion piece.

Then again, that's not quite fair to Rithy Panh. The Cambodian director has spent his adult life pondering the appalling, absurd atrocities the Khmer Rouge visited on his country. The Missing Picture, an extension and an elaboration on earlier projects, owes no debts to any other film-maker. Yet both Panh and Oppenheimer have taken risks in employing unlikely modes of representation: while the latter allowed the perpetrators to re-enact their crimes, Panh makes use of disconcertingly cute clay figures.

The dolls are required because – as the film’s title suggests – the survivors of Pol Pot’s deranged Year Zero project were left with few reliable images of the catastrophe. What we do have are streams of propaganda newsreels showing an agrarian utopia joyfully carving itself out beneath Indochinese sunlight.

Panh's juxtaposition of those elaborate lies – "The revolutions promise existed only on film," we hear – with more reliable (though childlike) clay dioramas triggers worthwhile ponderings about the unreliability of the moving image. The creations give us back life before the takeover in all its vividness. There is something of Marjane Satrapi's Persepolis in these rememberings of a flawed idyll unaware of imminent destruction.

Veteran viewers may still think of the historical events as current affairs. A younger generation will, however, learn much about the dangers of worshipping unmediated ideology: the Khmer Rouge killed millions in their efforts to dismantle the machinery of 20th century society. But, for all the film’s innovation, it is the raw emotion of the spoken narrative that leaves the most lasting effect.

“They had their orders,” the voiceover notes of the soldiers. “Never touch the enemy by hand. “The enemy. That’s me.”