Ryan Fleck and Anna Boden, Mississippi Grind

The Ryan Fleck and Anna Boden short films – Struggle and Gowanus, Brooklyn –  debuted in Park City in 2003 and 2004, the latter tying with When The Storm Came for the Short Filmmaker Award.

The partners and longtime collaborators graduated to features and brought Half Nelson to the festival in 2006, followed two years later by the Dominican baseball drama Sugar.

Now, after a seven-year detour that saw them branch into television, the duo are back at Sundance with Mississippi Grind starring Ryan Reynolds and Ben Mendelsohn as gambling buddies who take to the road to pay off debts.

Regardless of how many times their names have graced Sundance marquees, Fleck says it doesn’t get easier when it comes to watching their films in front of an audience for the first time.

“You can never gauge how people will respond,” he says. “Every time it’s a surprise. But even if they don’t like it, at least we’re pushing buttons.”

The easy part, says Boden, who shares an editing credit on the film, was the idea for the story. When shooting Sugar in towns around Iowa, she and Fleck visited riverboat casinos, which for Boden are “a world of gambling unlike most of what you see on screen – they were no Vegas or Atlantic City.”

She instead equates them to tiny places stuck in another time, where locals like the characters depicted by Reynolds and Mendelsohn sit around all day, gambling away what little money they have.

“Those casinos and the fascinating community within them helped influence the development of Curtis and Gerry’s relationship. You would hear people talking about the funniest of things. They weren’t the high-powered card sharks I had imagined.”

The rainbow motif referenced throughout the film was one example of inspiration drawn from a local gambler waxing poetic.

“I remember overhearing a guy tell his table, ‘I drove to the end of the rainbow once – right to the end of the trees,’ and I couldn’t help laugh,” says Boden. “I knew we had to include the rainbow somehow.”

The co-directors – who met at film school in New York – unexpectedly took to a bit of poker-playing themselves.

“We weren’t great, but we certainly had some fun moments just hanging out and learning more about the wonders of poker and its players,” says Boden.

The experience helped mould Mendelsohn’s character Gerry, a down-on-his-luck middle-aged guy who desperately wants someone to latch onto, as well as the charming Curtis played by Reynolds, who is the answer to all Gerry’s problems.

“Curtis is that guy who walks into a room and spreads magic like a leprechaun,” says Fleck. “And let’s face it, who wouldn’t want to latch on to Ryan Reynolds? I certainly would.”

When asked about the interplay of addiction issues, Fleck and Boden immediately insist Mississippi Grind is not another Half Nelson, explaining that the earlier film was not primarily about addiction.

“Although these are people struggling with their demons – and unable to cope with adulthood – at the same time, we wanted it to have a certain life to it,” says Boden. “We wanted there to be humour and to capitalise on the need for human connection.”

This time the film-makers found themselves blending genres in their screenplay.

“The characters started off one way, but as we went on, they were tweaked continuously, becoming more full and lived-in,” says Boden.

“We knew we wanted to make a road movie but we also needed conflict and strong character development,” says Fleck. “Since we were having such a good time in the casinos when filming Sugar, we suddenly had a road movie with elements of gambling and friendship – giving it a throwback to 1970s road movies á la Robert Altman’s California Split.  

“Not all of our projects start that way,” says Fleck, “but for this, we wanted to play with different genres, while also attempting to turning others on their head.”

Reynolds and Mendelsohn, along with an unrecognisable Sienna Miller who plays Curtis’ girlfriend, rehearsed very little, giving the acting style a more natural feel.

“We read through the script together and talked about certain things but it wasn’t traditional rehearsals at all,” says Boden. “We aren’t the type of directors that say scenes have to be played exactly per the script, so it was a very informal way of working with the cast.”

Backed by Sycamore Pictures, Fleck and Boden worked closely with cinematographer Andrij Parekh and music supervisor Scott Bomar to create a homage to America’s landscape along the Mississippi River.

Production lasted 35 days and they shot mostly in Louisiana to take advantage of tax incentives. B-roll and specific exterior scenes like scenes at the dog races and horse tracks were shot in nearby states including Iowa, Arkansas and Mississippi as well as Louisiana.

This is the fourth collaboration with Parekh, who filmed on 35mm to best reflect the spirit of vintage Americana. The cinematographer used 35mm (2 perf), which gave the shots a wider format and scope and allowed for long lenses and soft backgrounds.

The dedicated landscapes were overlaid with Rhythm and blues tracks that Bomar worked diligently to clear with the license holders, with some fees nearing six figures.

“We had a friend that gave us hundreds of tracks to listen to when writing the script,” says Fleck. “But when it came to using them for the film, we knew some would just not be affordable.”

The two give credit to a few of their own musical suggestions that made it in, including Furry Lewis (Shake ‘Em On Down) and a Frankie And Albert song that is played in the final scene. 

“We wanted that real Memphis bluegrass sound to emanate throughout – and we just about managed to do that.” 

Looking ahead, the pair are developing projects although an expectant Boden, now in the final trimester of her pregnancy, says a break is on the cards. “I couldn’t help that one.”

• WME Global represents US rights and Annapurna International the rest of the world.