For the Duplass brothers' particular style of storytelling to work, they need to find very small moments that have overwhelming significance for their characters. To that end, they've cooked up a rock-solid premise with The Do-Deca-Pentathlon.
The movie stars Steve Zissis and Mark Kelly as Mark and Jeremy, two middle-aged brothers who are decades deep into a sibling rivalry that's pretty much defined who they are as individuals. When they were teenagers, they invented a 25-event competition that ended controversially and led younger brother Jeremy to talk smack about it to Mark for years afterwards.
When Mark, whose doctors have told him to avoid stressful situations, brings his wife and son to his mother's house to celebrate his birthday, Jeremy, now a professional poker player, makes a surprise appearance. He immediately begins jabbing at Mark's psychological wounds, and pretty soon the two are attempting to redo their epic contest on the sly -- Mark's wife doesn't want him to have a breakdown.
As with all films by the Duplass brothers, the actors make or break the project, and the duo at the heart of this picture deliver. Zissis is quite good, especially in the movie's opening third: Mark seems to choke on everything he says because he's so full of repressed anger. Kelly turns Jeremy into the perfect antagonist as he takes great pleasure in needling his brother, while also understanding that this constant confrontation is the only way he can show Mark that he cares about him -- he's a douchebag with a heart of gold.
There aren't many surprises in The Do-Deca-Pentathlon -- we can see the plot twists coming fairly easily -- but the actors are appealing and the Duplass brothers have gotten very adept at knowing when to cut away from a scene. Even though their films maintain an improvised feel, none of the sequences linger; once they make their dramatic point, the next one starts. Couple that efficiency with the movie's short running time, and you've got a small, simple, and successful indie.