City of God was an exhilarating and eye-opening immersion in the life of Rio de Janeiro’s underclass. I’d call it a landmark in Latin American cinema, only that sounds kind of pompous, and I don’t have anything like the grounding in Latin American film to make such a claim.

After some controversy among the team who created the film, its writer Jose Padhila went on to write and direct Elite Squad, which revisits the same territory — but this time through the eyes of Rio’s police. The film was a Golden Bear Winner at the Berlin Film Festival in 2008, but my response to it was muted compared to its vibrant predecessor.

That reaction is only partly due to the sense of familiarity that Elite Squad conjures. More, it’s to do with a question about what Padhila intends for the film, how that affects his choices as a writer and filmmaker, and how they in turn shape my feelings.

The symptom of the problem, as I perceive it, is a voiceover. It’s delivered by the captain of an elite police squad, who reflects on the careers of two young recruits to his team. Problem being that the voiceover tends to distance you from what’s happening on screen, and at times is frankly redundant. You can see what’s going on without having that information reinforced by dialogue, and for me at least it becomes more irritating still since the voiceover is intended to shape my emotional response, one that I was perfectly happy about and don’t want manipulated.

The other issue is more fundamental, and is why I call the voiceover a symptom rather than the problem itself. Padilha has chosen to make his film what amounts to a drama-documentary, one that stresses the facts of life within the police force. It’s a choice that sacrifices story and emotional impact for spoonfeeding the audience with admittedly fascinating information.

For instance, seeing the mechanics working on the police cars cannibalising a new vehicle to put parts into two others, tells you a lot. Finding out that the captain of the squad is on the take, and having the cheek to swipe the protection money that’s going his way to patch up the squad’s vehicles, is fascinating — but it doesn’t lead to any larger payoff. It’s the picture being built up that Padilha is interested in, making sure we get a sense of what this facet of reality is like.

And that’s fine, if you’re intent on using film as a polemical device. I have no problems with that. The history of cinema is littered with examples — Russian filmmaking is intricately tied up with propaganda, from the films themselves to the way they were shown on special cinema trains to audiences dotted about the vast Soviet Union. Then there’s the films made about the Royal Mail that are so celebrated for their visual style and John Betjeman scripts. And what is advertising if not a form of polemic? The industry has given us directors from Ridley Scott to Duncan Jones, and more are coming through all the time.

I’m not averse to Padilha’s stance with Elite Squad – it’s just that I find it a less powerful film than City of God since its function seems more to inform than to engage. And that seems to me to indicate a willingness to sacrifice the full potential of what film can do in favour of doing something more didactic and narrower in conception. Which is just one reason why directors are remembered for their feature films and not their party political broadcasts, however sincerely motivated the latter may be.