Edward Snowden’s name will appear in history books decades from now. But in what light? Will he treated as a civil liberties hero for exposing America’s surveillance system or as a criminal who weakened U.S. security?

It’s obvious what Oliver Stone thinks. The famous director deploys his febrile style to present Snowden as a lonely hero who gave up everything he believed in, and then risked his life to lift a choking cloak of digital surveillance.

The result is a sprawling, globe-trotting movie that begins with Snowden as a young Special Forces try-out who learns “there are other ways to serve your country.” The film then whizzes from Washington, D.C., to Switzerland to Japan to Hawaii, cracking open the secrets that Snowden exposed in a fateful meeting with journalists in a Hong Kong hotel room.

As a popular account of the surveillance state, Snowden gets it right. It breaks down just how U.S. intelligence agencies built vast computer programs that swept in every American’s phone records and text messages, and then also hoovered up everyone’s email using network tentacles into big tech firms, including Google, Microsoft, and Yahoo.

Stone and screen writer Kieran Fitzgerald obtained the details in the film through multiple interviews with Snowden in Moscow, where the North Carolina native has chosen to live in exile after the Justice Department charged him under the Espionage Act. (It’s not clear how long he will remain there—a giant PR effort, including Stone’s movie, is underway as Snowden’s supporters lobby the U.S. government to grant him clemency or even an outright pardon).

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The movie also accurately presents the legal foundation—or “the big ass rubber stamp” in the words of one spook—that the U.S. used to build its surveillance architecture, and does so in a way that doesn’t drag down the action.

Alas, if only there were more such action. Despite a real-life narrative stuffed with secrets and suspense, the film version quickly feels bloated as Stone treats us to scene after scene of Snowden struggling with his inner dilemma and, especially, with his devoted girlfriend, Lindsay, who is a major character in her own right.

The Ed-and-Lindsay plot serves a purpose. It shows how hacking is not just a political mission but a personal one too (yes, Snowden creeped on her computer). And the audience can relate to Lindsay’s ordinary person life, as opposed to the paranoid matrix that Snowden and the other tech types in the film inhabit. But overall, the relationship subplot just adds more clutter to an already overstuffed movie that also includes too many scenes of journalists puttering around the Hong Kong hotel room.

One wishes this had been told as a thriller not a melodrama. But Stone’s vision was to tell the story on the same plane as his Vietnam epic, Born on the Fourth of July, and so Snowden’s personal arc became indispensable.

The result can be overbearing such as when, near the climax of the film, Snowden must confront his former mentor, who is depicted as a giant head on a giant computer screen bearing down on the protagonist. It hits the viewer with all the subtlety of, well, an Oliver Stone flick. Despite the superb acting of Joseph Gordon-Levitt (who bears a striking resemblance to the real Snowden—who turns up at the end of the movie), the movie feels about 30 minutes too long.

But for tech or security aficionados, the film is a must-see since it offers up details that go well beyond what we know from the newspapers. It will also go a long way in educating the public about Snowden’s activities, and framing popular perceptions of someone who will become a major figure in American history. 6/10 (debuts Friday)