Barely 16 years after adopting its constitution, Ghana has had a history of violent coups, as the man with the most guns ruled the country. And even under democracy, there have been charges of fraud and corruption. But observers and security personnel are working to make sure that this election goes smoothly, proving that the nation is moving forward. Still, both leading parties declare themselves winner in a tight race that triggers a contentious, volatile run-off , after which one remote region ends up casting the deciding votes.

The film is beautifully shot and edited, with a gorgeous score that makes it feel almost like a thriller. The filmmakers have close access to each candidate, and they essentially narrate the film along with electoral experts, journalists and activists. Enormous crowd scenes are shot with a fluid intimacy that takes the breath away, while the detail in observational clips let us feel the lively rhythms of daily Ghanaian life. It's especially amazing to watch officials count the ballots in the middle of exuberant street parties.

This is a fascinating exploration of how a nation shifts from military to civilian power, as personified by former military strongman Rawlings who established the 1992 constitution. The film also explores Ghana's history as the first black country to gain independence in 1957 and its struggle to build a new nation on the foundations of colonialism. Western interests have continued to be a problem, including a 1966 CIA-orchestrated coup. The question now is whether oil and gold are helping the nation prosper or just a few fat cats.

Like everywhere on earth, the people don't trust politicians who make promises but fail to meet the need for food, health care and education. So the transparency of the entire election process is hugely inspirational: figures this raw simply don't lie. Sure, the culture of machismo is still a huge problem, causing bursts of violence. But even with some outrageous twists and turns, the fact that Ghana peacefully transferred power between opposing parties means that its democracy is on the right road.

Some 20 cameras captured the Chemical Brothers' performance on 31 July 2011 at Japan's Fujirock Festival. Director Smith says, "I wanted to capture what it is like to experience the show from right in the middle of the crowd." And to a degree he accomplishes that, showing the concert from the audience's point of view, with a sense of wonder at the elaborate light show and visually arresting projected images that accompany the music while the musicians themselves hide in their electronic cocoon in the middle of the stage.

In addition, he turns his cameras on the crowd itself, picking out a few people to show repeatedly as they ecstatically enjoy the music. And this is only the first heavy-handed touch Smith indulges in, essentially telling us that we should be feeling the same sense of uncontrollable emotion. To augment this, he indulges in crashing edits, fast zooms and lots of visual trickery. But to be honest, a more traditional concert-film approach would have conveyed the experience much more effectively by not over-egging everything.

Because the music is genuinely thrilling, recorded with pristine clarity and depth on the soundtrack. The Chemical Brothers are Manchester duo Rowlands and Simons, who we occasionally see in their shadowy cluster of keyboards and computer screens. But most of the time we are watching the audience or the astonishingly oversized video images, which are seriously impressive on their own, especially when inventively combined with smoke, lights and a witty use of the location itself.

Clearly the crowd loves every minute of this amazing show. But as a cinema audience, it's not quite so accessible. Sitting in a theatre might be the closest many will come to this kind of epic concert performance, and the duo's followers will revel in the chance to experience the music in this way. But the wobbly camera movement, quick-cut edits and over-reliance on the amazing visual effects actually manages to undermine the Chemical Brothers' wonderfully textured music. And the fact that the film never properly portrays the musicians leaves newbies feeling completely left out.

At the peak of the conflict in Afghanistan in summer 2009, a company of US marines are dropped into hostile territory to fight insurgents and shift the momentum in the war against the Taliban. "We are experts in the application of violence", their leader reminds them, "with a clear purpose and a clean conscience." The film follows 25-year-old Sergeant Nathan Harris over several months in the field, then back to North Carolina. But incorporating his experiences and injury into life back home isn't easy.

Shot with clear-eyed intensity, the cameramen nestle right in with the soldiers as they manoeuvre for position and then engage in brutal gun battles. This approach sharply observes the raw emotions in the line of fire, as well as how they haunt veterans back at home. Structurally, the film flickers back and forth to mimic the jarring battlefield memories. Nathan talks about how the only way to get on with life at war is to accept the fact that you can die at any moment, so it's no surprise that he struggles to cope with the mundane details of a fast-food drive-up window.

Shot like a narrative feature, the film is packed with terrific scenes that are chilling simply because of the subtext. While no one can question the soldiers' motives, their methods are deeply troubling. One officer tells the Afghans that US forces are here to protect them for quite some time, only to be immediately asked to leave because they're making the area too dangerous for the children. Back home, Nathan cuddles his pistol while his wife sorts out his medication.

Nathan longs to return to the frontline, but his injuries mean that he'll never walk without assistance. On heavy medication, his thoughts turn to violence and suicide, and filmmaker Dennis remains intimately close right through it all. Clearly, no young man should have to deal with this kind of internal horror. And Nathan's experiences in Afghanistan will be with him for the rest of his life, physically, mentally and emotionally.

There isn't a narrative, although the film is arranged to recount an epic journey using voice-over readings from authors like Homer, Sophocles, Milton, Shakespeare, Beckett and Nietzsche. There are also title-card quotes, songs and music, including some pieces performed in old film clips (such as Leontyne Price singing Motherless Child). Meanwhile we see a collage of old film clips and crisp new footage shot in snowy Alaska featuring silent men in yellow, blue and black parkas that obscure their faces.

The film has a remarkably emotional tone, even though it's difficult to make much sense out of it. While the new footage is beautiful, its links to the other material is rather tenuous. Occasionally there's a clever visual parallel between images. Although who these parka-wearing guys represent is a mystery; they're often immobile, just standing in the middle of nowhere. And there are also glimpses of what looks like a homeless man in a deserted city.

It's sometimes fascinating to see how scenes have been assembled together, as the grainy black and white contrasts strikingly with the sharp new imagery. And many of the old scenes are strongly evocative, as they show scenes of destruction, poverty and a variety of faces that hint at racial themes in post-war Britain (most of the people are black or Asian). Also, as there is a general sense of the journey progressing, including a lot of clips that feature modes of transportation.

Yes, all of this is very beautiful, but there are art films and there are ART films. This one's so high-minded and impenetrable that it begins to lull us to sleep as it goes along. The music sometimes jolts us awake, as do scenes of fires and floods and several fascinating faces. It's the kind of movie that some film critics read a lot into, declaring it a work of genius. And there's no doubt that Akomfrah is a gifted artist who is saying something important. Watching his film is like staring at a moving painting.