Something I was very conscious of when Alien vs Predator came out was that it was an art form (objectively, that is) that emerged from art based on other art, and come back around to occupy the position of the art forms that generated it.

In simpler terms, someone wondered how cool it would be for the monsters out of Alien and Predator to fight and built a video game about it. It became popular enough for a screen producer to believe it might make a marketable movie, and writers were hired to convincingly portray a world where the aliens and predators could coexist.

What's this got to do with Roger Ebert? In the same way, someone whose job it was to comment on movies became such a commanding figure in the field his life has become a movie. It's a movie about a guy who was all about movies, and who became a larger cultural fixture than many of the movies he critiqued – a classic Ouroboros (that ancient Greek symbol of the snake eating its own tail) of art imitating art that imitates art in turn.

If you don't know or care who Ebert is or you don't think he was the genius most of the film firmament was, you might think the title is a bit grandiose, the same way Baz Luhrmann's Australia seemed to want to be the definitive statement on the titular country. This, the title seems to say somewhat smugly, is how life should be lived if you're a movie lover, and none of us can ever be as good as Ebert.

However, the film itself makes it pretty clear that while Ebert was a good writer (which even Stephen King observed are a dime a dozen), he was merely in the right place at the right time when he was appointed film critic of the Chicago Sun-Times in the late 60s. Did he win a Pulitzer prize because he was brilliant or became he was wildly popular?

As Life Itself details, fate delivered Ebert the most elusive thing a writer can have – a platform. He had the pages of a newspaper to espouse his view of the world every day, so when the world evolved/descended into a screaming mass of badly-spelled blogs and fanboy forums, he was already in a position to stand out. There's a reason the most famous people all come from old media rather than YouTube (although as I write this, that's changing by baby steps). That, as much as any writing talent, made him what he was. He was famous, so people cared what he thought.

As a biography it paints what looks to be a pretty complete picture, not shying away from his days of drinking and shagging around a Chicago city bar where writers and newspaper columnists used to congregate and argue. You can almost feel director Steve James' love for the idea, subconsciously painting it with the same mystique we might use to describe some hotel in early 20th Century Paris with Fitzgerald and Hemingway lounging around fighting about politics.

It's not hagiographic, addressing Ebert's personal life and the race issues his marriage to the African American Chaz raised, but James (like everyone) is more interested in paying tribute to a guy everyone says is a great man rather than finding dirt. Of course, we're talking about a professional writer – there wouldn't have been many sordid events in his past worse than drinking and infidelity (which nobody's suggesting).

Filmed right up to Ebert's death in 2013, there's an eerie poignancy as James exchanged increasingly short and curt emails from his subject, put in hospital for the last time and seeming to know the end was coming. It gives the rest of the film a sense of closure, healing and celebration it wouldn't have had otherwise.

And in looking at Ebert, it casts a clever eye over the subject intimated in the title. Ebert loved movies, and what else do movies teach us about but life itself? It manages to look both at him and through him at something you'll already love if you go to the trouble of watching this film, so it's almost irrespective of Ebert that it succeeds.