Chris Marker, who died on his 91st birthday in 2012, was a filmmaker beyond category. It is often said that he transcended or defied the conventions of genre. Most famous for “La Jetée,” his 1962 time-travel tour de force, 28 minutes long and composed almost entirely of still images, Marker also seemed to have freed himself from the strictures of time.

“Level Five,” a passionate and cerebral science-fiction adventure made in 1997, belongs equally to the past, the present and the future. Never released in the United States, its themes are a bit nostalgic and some of its technology looks dated, but there is nothing else in theaters now that feels quite as new.

Is “Level Five” an essay film, a documentary, a techno-thriller or a mystery? The answer is yes, in an arrangement that is characteristically playful, ruminative and melancholy.

Much of “Level Five” consists of the straight-to-camera testimony of Laura (Catherine Belkhodja) as she reflects on the legacy of a vanished lover and collaborator, who disappeared while researching an interactive video game.

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The subject of that game is the Battle of Okinawa, which is also, therefore, among the subjects of the film. Interviews conducted in Japan are interspersed with ghostly archival footage to recall a horror that much of the world has forgotten. After U.S. forces landed on the island and gained a strategic advantage, the Japanese military, determined to fight to the last man, began a campaign of executions and forced suicide against the civilian population, more than 100,000 of whom died.

Marker’s calm, mournful voice-over notes that this was one of the worst instances of slaughter in World War II. His video-game designer imagines that it might be possible for players to undo this dreadful history and arrive at different outcomes, and it is perhaps this hope that leads him astray.

But “Level Five,” though it is in part a rigorous, informative and morally powerful historical documentary, is also a meditation on the relationship between the fixity of the past and the flux of memory. It wonders, in a way that feels joltingly contemporary, about how the images captured, invented and disseminated by various forms of technology — including cinema itself — affect what we know about the past and ourselves.