Actor Joseph Gordon-Levitt gives a credible portrayal of Snowden as he becomes increasingly troubled by what he finds in his posts as a security specialist. Through contacts with his fellow experts and his observations he recognizes the threat to our freedoms. He is not a showboat of a whistleblower, but a quiet man of conscience who eventually feels it his duty to tell the world what is going on.

We see him in a relationship with his girlfriend, Lindsay Mills, nicely played by Shailene Woodley, and the problems caused between them by his need for secrecy and his dedication to work. (A postscript at the end of the film informs us that she has joined him in his exiled life in Russia.)

What Stone does exceedingly well is to escort us through the maze of the computer world in the secrecy atmosphere that prevails while a battery of experts fulfill responsibilities for the projects assigned to them. This is tough to dramatize, given all of the tech talk and visuals required to provide us with insights to what the surveillance is about and its extent. The show and tell is presented with counterpoint of what is going on outside of the computer rooms so that the story is moved along. Director Stone and his co-screenwriter Kieran Fitzgerald do an excellent job in this respect.

Thus we see the reality of Snowden’s world that informs his character and ultimate decision. There is also suspense as Snowden copies files, always looking up to see who could be watching, and also suspense as he schemes to evade security checks in managing to flee to his Hong Kong rendezvous with those to whom-he tells his story--Laura Poitras, played by Melissa Leo, who made the documentary “Citizenfour,” and two journalists, Glenn Greenwald (Zachary Quinto) and Ewen MacAskill (Tom Wilkinson).