"Promised Land" offers an experience that’s alternately amusing and frustrating, full of impassioned earnestness as well as saggy sections.

Director Gus Van Sant has the challenging task of taking the divisive, high-tech practice of fracking and trying to make it not just human but cinematic. Working from a script by co-stars Matt Damon and John Krasinski, based on a story by Dave Eggers, he succeeds in fits and starts.

The impoverished small town that’s the tale’s setting, a place in need of the kind of economic rejuvenation that extracting natural gas could provide, is full of folksy folks whose interactions with the main characters don’t always ring true. "Promised Land" has its heart on its sleeve and its pro-environment message is quite clear, but it’s in the looser and more ambiguous places that the film actually works.

Damon, collaborating with Van Sant for the third time as both screenwriter and actor (following "Gerry" and the Oscar-winning "Good Will Hunting"), stars as Steve Butler, a salesman traveling the country on behalf of a bland behemoth of an energy corporation. Having grown up on an Iowa farm himself and seen how an economic downturn can devastate a small town, Steve is a likable everyman who seems genuinely invested in what he’s selling. But he’s also a pragmatist, as evidenced by the playfully cynical give-and-take he enjoys with his partner, Sue, played by a dry, sharp Frances McDormand.

Known for his efficiency in persuading rural residents to sell their land for the drilling rights, Steve runs into an unprecedented challenge when he and Sue arrive in the depressed dairy farming community of McKinley in western Pennsylvania. Outspoken old-timer Frank (Hal Holbrook), the high school science teacher, and flashy, charismatic environmental crusader Dustin (Krasinski) dare to question the company’s methods in increasingly vocal ways.

But even as Steve struggles to close the deal, he finds himself growing entrenched in the daily rhythms of this idyllically charming little nook of the heartland. Rosemarie DeWitt co-stars as a winsome grade school teacher with dismayingly half-baked romantic connections to both Steve and Dustin; essentially, it’s as if she’s waiting around the local watering hole on karaoke night, hoping that some cute, exciting outsider will waltz in and woo her. The actress, and the character, deserve better. Similarly, Sue enjoys a brief flirtation with the sarcastic convenience store owner (Titus Welliver) whose character is underdeveloped and yet so briefly intriguing, you’d like to know more about him. All of this feels half-heartedly wedged-in.

Steve and Dustin obviously function as two sides of the same coin, but their confrontations don’t crackle the way they should because everyone involved is just so darn nice. But there is an appealing gray area suggested in Damon’s character. For a while, we’re not quite sure whether he’s a true believer or an opportunistic climber — that is, until some major and implausible plot twists make his stance forcefully, indisputably clear.

Review by Christy Lemire / Associated Press