At times throughout Citizenfour, you’d be forgiven for thinking that you were watching a taut political thriller, about a fictional superstate with surveillance powers that George Orwell could only dream of.

But, in reality, Citizenfour is a sobering look at the very real world of the National Security Agency (NSA) and the UK’s Government Communications Headquarters (GCHQ).

The documentary focuses on whistleblower Edward Snowden, showing footage of him before and after he was revealed to the world, a focus made somewhat ironic by Snowden’s repeated assertions in the film that he’s not the story.

The documentary is clearly aware of this fact, which is perhaps why it has come out a few years after the original leaks, giving time for the stories themselves to gain the publicity and attention they so deserve.

Snowden is revealed to be a much more complex and nuanced character, than he has been previously painted in the press and by supporters. He is not shown as a monster, a criminal or someone out for fame, and equally he is not shown as an all-out hero.

While Citizenfour is clearly sympathetic to Snowden, it shows how he comes to terms with the immensity of what he’s done, the struggle of abandoning his girlfriend and family, and how he ended up in Russia against his original plans.

It’s a gripping, if somewhat depressing, tour de force in journalism, all set to an ominous, dark soundtrack.

For those not up to date with the ongoing surveillance scandal, director Laura Poitras does an admirable job of covering the key stories and explaining the more technical aspects like metadata, without distracting from the main narrative.

We learn how Snowden, using the moniker Citizenfour, contacted Poitras and began leaking information. From there, the film follows their time holed up in a Hong Kong hotel with Glenn Greenwald – going through the troves of classified information he’d leaked, before bringing the story into the present.

Often the documentary sounds downright fantastical – Snowden met Poitras in the lobby by telling her to approach a man playing with a Rubix Cube and go through a set conversation.

At one point in the hotel, the fire alarm goes off repeatedly, spooking Snowden out. Later Snowden finds out that the rent for his home has suddenly dried up despite being already paid, while construction trucks mysteriously appear outside his home.

It’s a gripping, if somewhat depressing, tour de force in journalism, all set to an ominous, dark soundtrack.

Citizenfour leaves many questions unanswered, and is far from the end of the story, something the film clearly shows in its ending. It concludes with its biggest revelation, confirming suspicions that Poitras and Greenwald have another source inside the NSA.

“This person is incredibly brave,” says Snowden, before being told that the NSA has an astounding 1.2 million people on its watch list. “That’s fucking ridiculous,” he concludes.