Technically, “One Day” is a romance film. But nearly as often as we see them, Emma (Anne Hathaway) and Dexter (Jim Sturgess) are just outside of love. They are, if you will, in a best friendship … and it’s complicated.

It’s an approach to the genre that fundamentally changes the focus. We’re not talking “The Notebook” kisses in the rain or the spunky sincerity of any given Katherine Heigl film. Hathaway and Sturgess portray a sensible relationship kindled in college and slopped through decades of suggested alcoholism, parents with cancer, failure to conceive and all-around complex lives.

“One Day” functions more as a montage than as a narrative. It’s built on a gimmick that allows the viewer several glances at the same day, July 15, starting in 1988.

The impression is that of a life in love flashing before one’s eyes — or perhaps one’s wedding reception. And so it is that the film feels like the Sparknotes of a more fully formed love story, skipping from chapter to chapter and apportioning near-equal weight to lonesome phone calls and — to avoid a tempting spoiler — much graver occurrences.

This is not to say that Hathaway’s fragile poise and nearly “Juno”-esque moments of offbeat sincerity or Sturgess’ swarthy British charm a la Hugh Grant don’t pay off. In fact, each and every character — however minor — is allotted remarkable depth and development; from the concerned but stoic father (“I don’t want a heart-to-heart. Do you?”) to the precious toddler daughter, the film is populated with characters who could viably sustain their own stories, and actors solid enough to uphold complex emotions in such slender parts.

Thus, with lifelike characters and bites of life in real time strung together like cranberries and popcorn around a Christmas tree, the audience is left with a finely crafted decoration, complete with warm fuzzy feelings and memories of priceless times both good and bad. The platonic emphasis adds much to the story’s emotional impact, tinting it to a story of two people and their crossing fates rather than a glorified college crush gone overly long-term.

But by the same token, the film plods, stuck in a menagerie of characters, days colored with halfhearted longing, and 20 years of two busy yet sorrowful lives.

Go expecting more drama than direction and more compassion than passion. Then take your seat in the theater with a yearbook mindset. The characters have got to mean the world to you; otherwise, the movie might not deliver.