Four stars

The importance of the family you make, rather than the one you're given, is at the heart of this low-budget independent American feature that just happens to have two enormous Hollywood names on the marquee.

A quasi-retelling of the Huckleberry Finn story, it follows the ambitious young dreamer Zak (Zack Gottsagen) as he escapes the confines of an old people's home.

Zak has Down syndrome and doesn't belong in such a facility, as kind-hearted carer Eleanor (Dakota Johnson) knows too well, but in their rural Carolinas backwater the care options for Zak are limited.

With the assistance of fellow inmate Carl (Bruce Dern), Zak does a runner, ending up a stowaway on a fishing boat that gets stolen by Tyler (Shia LeBeouf).

The two of them end up on the run from two angry local fishermen, Duncan and Ratboy (John Hawkes and Yelawolf), whose livelihood Tyler has taken, along with a river full of mud crab pots.

He's also committed a little bit of arson.

Zak and Tyler journey up rivers and marshlands on boat then pontoon.

Tyler is running from his past actions and Zak running towards the dream that fuelled his years in the old people's home.

He wants to train at the academy of the Salt Water Redneck (Thomas Haden Church), star of a local television wrestling show of which Zak has a library of VHS tapes.

On a parallel journey, following the roads as the boys follow the rivers, is Eleanor, looking out for her charge with genuine concern.

This film moves at a slow pace, echoing the challenges of geography its protagonists take on and the heat of the estuarine locations.

It manages to say a lot with limited dialogue.

The Peanut Butter Falcon brought to mind a handful of similarly slow and deep American Indies of years gone, particularly Jeff Nichols' 2012 film Mud.

In an America that, in the media at least, seems a less compassionate place than it used to be, first-time writer-directors Schwartz and Nilson debut with a balm of emotional warmth and hope.

In terms of disabled representation, it scores high.

Gottsagen is the emotional heart of the film, neither backgrounded, not a life lesson.

Schwartz and Nilson met him at an acting workshop and were inspired to craft a film around him.

His characterisation is layered and complex, and a Huck Finn of sorts to LeBeouf's Tom Sawyer-like Tyler.

LeBeouf anchors Gottsagen and their relationship feels real.

As writers, Schwartz and Nilson craft simple dialogue that gets to the heart of the story.

"Am I gonna die?" Zak asks as Tyler convinces the poor swimmer to float downstream with him.

"Course you're gonna die, it's just a matter of time," replies Tyler.

"That's not the question. Question is are they gonna have a good story to tell about you when you're gone?"

The filmmakers enlist music composer Zach Dawes for a bluegrass-heavy soundtrack that warms every scene it appears in and had me downloading it before I left the cinema.

Think O Brother, Where Art Thou?

Just what is a peanut butter falcon?

It's a bit of writerly silliness that ends up being the wrestling name Zak fights under. It's a sweet bit of nonsense.