Ostensibly a testament to terrestrial beauty and human ingenuity, nature doc James Cameron's Deepsea Challenge 3D feels like a feature-length humble-brag. The film's main subject isn't supposed to be Cameron himself but rather his record-breaking submarine voyage to the bottom of the Mariana Trench, the deepest recorded spot on Earth. But Deepsea Challenge has too little interest in anything that's not Cameron's personal experience.
The film begins with a dramatized account of Cameron's boyhood fantasies of oceanic exploration. After that, he explains how his filmmaking career has dovetailed with his yen for deep-sea diving, from writing and directing The Abyss in 1989 to using remote-controlled robots to explore the Titanic's wreckage in 2001. Thankfully, the scope then broadens slightly, and shows the engineers of his sub, the Challenger, working with Cameron to test the experimental submersible's ability to withstand close to a dozen tons of pressure. Cameron even repeatedly praises the Challenger's dedicated (i.e., 16-hour workdays) crew: "They are the heart of this mission, and it is them."
But the film never takes time to humanize the blue-collar egghead subordinates the way one of Cameron's fictions might. We never learn what they individually contribute, or what their stake is in Cameron's success. Similarly, the extraordinary footage he returned with from his 2012 dive isn't contextualized beyond dazed, in-the-moment observations, like "I think I see a critter" and "[An octopus] is chasing us! What a mighty warrior." Cameron may be both a pioneering filmmaker and explorer, but Jacques Cousteau he ain't.