When I attended this year's London Film Festival, Snowden was quite high up on my 'ones to watch' list. Oliver Stone's latest film casts Joseph Gordon-Levitt as one of the world's most well-known whistleblowers. It casts light on events that happened as recently as 2013 and revisits the real world issue of mass surveillance and 'too much information'. The end result is a solid film that tells the story but unlike Snowden himself, doesn't break too many boundaries.

It's important to note that this is, indeed, a true story. Edward Snowden is a name you'll remember from recent headlines of this past decade, even if you don't remember/know too much about the events that put his name there. Director Oliver Stone has done a great job of putting the whole thing together simply but effectively, mixing up the timeline a little to re-break the news story. It begins with Snowden's first serving of the USA in 2004 - and the film does deliver in servings in a different sense, chapter by chapter building up the bigger picture that leads to the outcome we're well aware of the entire time: Snowden leaking thousands of documents of national security into the public domain. Stone and Gordon-Levitt actually met with Snowden several times, and consulted writers on the topic, so it definitely lends to its authenticity and knowing you'll get more than just a Wikipedia search result.

The film also puts a spotlight on the relationship between Snowden and his girlfriend Lindsay Mills (played by Shailene Woodley). In fact, the two plots become pretty much intertwined and you begin to wonder how much of this has been played up for the Hollywood romance card. For me, the spotlight was shone a tad too brightly. It does, however, bring a healthy political debate into the domain early on in the 134 minutes. It also adds the much-needed human element to the whole thing, and makes "Ed" a guy you want to back - both in his career and love life. It's all very sweet really, especially when you see the sacrifices Lindsay's made for her man including moving to live with him in Russia now.

The supporting characters are more polarising - there's Rhys Ifans as Corbin (not Conan) O'Brian, a CIA senior who oversees new recruits and seems to be a BNIC (big name in CIA). Or in the film version, anyway. He's an exaggerated character there to give you the flip side. He's the mentor figure...he believes in Snowden, takes him out for country walks and shooting and stuff... Then there's Nicholas Cage who plays professor Hank Forrester, and stops you right there to say, "Blimey, there's Nicholas Cage." His role also extends to voicing another opinion and speaking the harsh truth. A very accomplished cast listing extends to include names such as Melissa Leo, Zachary Quinto and Timothy Olyphant, all given quite minor roles.

As mentioned, 134 minutes is unnecessarily heavy; the revelations are gradual but the sense of urgency is almost lost in most places even though it's supposed to be a blatant race against time. It's a solid portrayal but I can't help thinking it could make much bigger waves of impact than simply retelling the story. It feels dramatic yet restrained, though I couldn't pinpoint where and how I'd make it go bigger and better (like this year's Spotlight, on a similar current affairs vein).

On the other hand, one really strong highlight is undeniably Joseph Gordon-Levitt's portrayal of Edward Snowden. It's not just the uncanny voice and the hair and makeup, it's his commitment to the role and ability to command attention as a softly spoken computer genius. I also feel as though I know much more about who he is as a person now, even if it is through somebody else. Obviously casting is an important choice, and they've done very well at it here. Whilst there are many Hollywood stars raising eyebrows through their portrayals of well-known people, JGL is not one of them.

From the get-go, Snowden's painted as a patriot. And the film rests on his disappointment with the government's dealing with spying, essentially. Spying on everyone, that is. You'll be making the decision of whether he still is a patriot, or whether he is a traitor, or simply someone with such a big moral conscience that he simply can't conform any longer. Whether you agree with his actions or not, it does open up a big conversation - one that definitely isn't had frequently enough even now three years after the story first broke. I remember having high school class debates many years ago over whether too much CCTV is a good thing or not, but now imagine that surveillance is everywhere...through your phones, the webcam you've forgotten about sitting on your laptop...  It's a big deal! It's also easy to personify agencies like the NSA, CIA or whoever, but it's clear what sort of personalities they are given in this film, and it's even clearer which side of the fence Stone sits on. Snowden is hailed a hero, but it's almost too much.

One flaw I'd point out is that it seems dreadfully easy for all these files to be obtained. Maybe the filmmakers simplified the process, but it is essentially a flash drive and a clever getaway car*. (*Not actually a car.) In the same way, I think Snowden is actually a bit easy in the sense that it doesn't feel nearly as groundbreaking as it ought to be - and is in reality. Still, it's well worth a watch and you'll walk away from the cinema knowing more than when you went in, reigniting the information debate. And that's not a bad thing at all.

Snowden is in UK cinemas on 9th December.