Cartel Land was one of 2015’s most successful documentaries, earning a cavalcade of critical praise and even an Oscar nomination. It’s not hard to see why; Matthew Heineman’s film combines a contentious contemporary issue – Mexico’s fraught, cartel-dominated ‘drug war’ and tensions along the U.S.A./Mexico border – with kinetic, ‘can-you-fucking-believe-they-got-that-shot’ cinematography. It’s the kind of documentary that spends as much time shouldering a camera into a firefight as it does on talking heads and dizzying drone photography.

All that flashiness cleverly disguises the failings of the film; nothing egregious, but little mistakes that compound to make Cartel Land lesser than it could be. For starters, its bifurcated narrative – half north of the Mexican border with ‘anti-cartel’ militia, half south with a crew of ‘anti-cartel’ Mexican citizens (each with decidedly shady motivations) – is a no-starter. The U.S.A. side of the story offers fleeting insights into the anti-authoritarian, largely-racist motivations of the militia, but flounders when trying to stand up to the excitement south of the border. Frankly, it distracts from the film proper, and should’ve been reduced – or omitted entirely – in the edit.

Thankfully, the story down being told down in Mexico is far more compelling. We follow a crew of disgruntled civilians, led by one Jose Mireles (nicknamed “El Doctor”), who call themselves the “Autodefensas” and wage a war – of sorts – on drug cartels and corrupt cops alike with the support of locals (who’ve suffered greatly at the hands of the cartels). Heineman positions their tale as one of nobility, heroism – a revolutionary uprising! But, of course, this is the real world, and it’s not long until the cracks start appearing the Autodefensas’ gleaming façade.

To reveal that the Autodefensas’ descent into all-out villainy – gradually, at first, torturing cartel members for information, influencing starstruck young women, before shifting into drug production themselves once the competition’s out of the way – is maybe a spoiler. But it’s no surprise, really, not if you have any comprehension of how humans – men – grapple with power (or, I dunno, if you studied Animal Farm in school). Heineman’s mistake is that in emphasising the heroic tale upfront, with thrilling footage of gunfights and tense standoffs with crooked police – he diminishes the really interesting tale of how the Autodefensas crumbled into corruption.

Were they corrupted, as the old saying goes, by absolute power? Perhaps – Cartel Land hints at that as it queasily chronicles Mireles’ “seduction” (or strongarming) of one of his female disciples. Or, maybe, they were rotten from the get-go, as Heineman implies late in the piece by revealing the backstories of Mireles’ compatriots, many of whom have their own background in the cartels. There’s even a Napoleon to Mireles’ Snowball, a gruff bearded gent who eventually asserts control over the Autodefensas.

Maybe it’s just me, but the specifics of such power struggles – crumbs tossed to the audience in between blasts of dynamic action – are far more interesting than the observation of the end product. It’s undeniably compelling – and affective – to watch the Autodefensas become precisely that which they set out to combat, but it’s also sort of trite. Good guys become bad guys and the nuances are smoothed over. For a film that describes itself as having “unprecedented access”, I just wish it could have offered some insight as well.