There is a great documentary to be made profiling the venerable Roger Ebert, who long held court as the most popular film critic in America and died at age 70 in the spring of 2013. Life Itself, a well-intentioned but enormously disappointing biodoc from director Steve James (Hoop Dreams) and producers Martin Scorsese and Steven Zallian, is not that film. Officially an adaptation of Ebert's bestselling memoir of the same title, the motion picture takes Ebert's last five months, as he battled cancer and faced a grim prognosis, and uses that period as a structural device. We get a series of flashbacks that take us through Ebert's colorful life and times, but keep periodically returning to his traumatic days in the hospital, throughout the movie, to watch Roger withering away and his wife Chaz and others preparing themselves for final goodbyes. The film has many problems, but the two most pronounced are connected: an excessive emphasis on Ebert's struggle with cancer, and overlength. It was appropriate, of course, for James to depict Ebert's heartbreaking final days, but scenes of his hospitalization take up nearly a third of the picture; the disease and physical suffering get so much screen time that they threaten to offset the overview of Ebert's accomplishments. By default, we empathize with Ebert's plight, and feel saddened by his sickness and passing, but this film begins to beg for sympathy, and that offsets the legitimate emotional pull that it would have otherwise earned. Ebert's legacy did not reside in his terminal illness; it resided in his work as a film critic and journalist, and his personal relationships with fellow film critic Gene Siskel and wife Chaz Ebert, and those should be the predominant emphases of the motion picture. The memoir's title is Life Itself and not Death Itself for a reason; accordingly, the documentary should be a celebration of Ebert's colorful and amazing life. The motion picture also suffers from its hagiographic approach. Anyone who has observed and followed Ebert over the years knows that, although he was enormously likeable and could be very charming on and off-camera, he was far from a saint, and James is less than honest with his presentation, perhaps for fear of tainting Ebert's image. For instance: there is a famous outtake from Siskel and Ebert and the Movies, shot in 1987, where Ebert and Siskel playfully insult and curse at each other. Around the beginning of that clip, Ebert snidely looks over at a cameraman and patronizingly chides, "This is not the part that's supposed to match, slick. Give it a moment's thought and what are we doing now? The promos." James includes the outtakes, for laughs, but cuts around the Ebert snarkiness. Why? Did he honestly believe that we would dislike Ebert for being a heel on occasion? The glimpses of his imperfections that we do get - such as a brief but fascinating discussion of Roger's alcoholism in the late '70s - are what really make parts of this movie work. They bring Ebert down to earth, making him seem more complex, human, relatable. There are also significant omissions here - it may not be as obvious to someone who hasn't scrutinized Ebert's activity over the years, but if you go back and comb through what does exist online, it's curious that James omitted what he did. Consider, for example, two stunning interviews on Later with Bob Costas that Siskel and Ebert did in the early '90s, that are both candid and revealing. Or Ebert's famous appearance on The Oprah Winfrey Show, where Roger turns up to discuss his date with Oprah in the mid-80s. Or - most glaringly - Ebert's secondary role, in the last few years of his life, as a trenchant and astute social critic through his blog. In the wake of the Aurora massacre, for instance, he wrote one of the most scathing and brilliant excoriations of the NRA and gun culture in the contemporary media. There is an image in the documentary that flashes on the screen, suggesting Ebert's pro-gun control activism, but if you blink, you'll miss it, and James skirts around any extended discussion of the matter. The problem may lie in James's decision to make the documentary a loose adaptation of Ebert's memoir, instead of simply doing an original biodoc on Ebert; perhaps he let himself be constrained by the content of the original work. The book was fresh, whimsical and poignant, with short, piquant chapters of various episodes in Ebert's life. James takes that same approach, but onscreen, for some reason, it feels too loose and scattershot. There are a few interviews from people like Jonathan Rosenbaum, Marlene Iglitzen-Siskel, and Scorsese (who is so funny that he lifts the film sky-high when he turns up) but also a fair number of people with ties to Ebert who are curiously absent, such as Winfrey, Richard Roeper, Hugh Hefner, Tom Shales, Rob Schneider and Vincent Gallo - the last two of whom famously ran into conflict with the esteemed critic. To be certain, some of the footage interpolated here is entertaining, but all told, this has to count as a missed opportunity.