Gabrielle Union, Pete Davidson and Lewis Pullman also star in Dito Montiel’s violent account of an uncomfortable family reunion that gets uglier once the patriarch’s shady past catches up with him.

The first question that pops up in connection to Dito Montiel’s dark crime comedy about a messy family reunion, Riff Raff, is how in hell he assembled such a cast of proven talents. Even if they never really mesh as an ensemble, there are pleasures to be had watching an Ed Harris–Bill Murray face-off, Pete Davidson as a depressed gangster, Gabrielle Union classing up the joint and Jennifer Coolidge bringing the tone crashing down as a sloppy drunk with a mouth like a trucker and a raging libido.

Reading Montiel’s doozy of a director’s statement, the thought arises that he might be a great pitchman. He likens reading John Pollono’s script to stumbling on an undiscovered Mamet play, then offers up a bunch of inspirational references to make your head spin — Goodfellas, No Country for Old Men, Reservoir Dogs, Blue Velvet and A History of Violence. It’s good to aim high.

But if you can spot anything but the palest imitative shadow of the idiosyncratic films crowding Montiel’s vision board, you have sharper eyes than mine. Maybe it all sounded more convincing at the casting stage.

“It’s amazing what family is willing to do for each other,” says DJ (an appealing Miles J. Harvey), the innocent observer who provides intermittent voiceover narration. That defining statement ties the film directly to Montiel’s interests dating back to his debut, exploring the volatile dynamics of fragmented families touched by crime. But the new one seems constantly at war with itself over whether to commit to the thriller or comedy side, ending up half-cooked in both.

The opening has sweet-natured DJ nervously pointing a gun at the head of Vincent (Harris), the man who has been a loving stepfather to him since marrying his mother, Sandy (Union). “Family can be complicated. Things go wrong,” says DJ as Montiel rewinds to the beginning to see what brought them to that tense moment.

Vincent is not at all pleased when his rattled son Rocco (Lewis Pullman) turns up unannounced with his very pregnant Italian girlfriend Marina (Emanuela Postacchini) — thanks to the two actors’ chemistry, the only believable relationship in the movie. The news that he’s about to become a grandfather does nothing to soften Vincent’s disposition.

He’s even more angered when they haul in his unconscious ex-wife Ruth from the car and drop her on the couch like a sack of potatoes. Once she’s awake, Ruth proceeds to hit the booze, hit on Vincent and pocket Sandy’s expensive cosmetics.

Montiel deftly interweaves flashbacks to provide some history. We see from DJ’s amusing previous encounter with Ruth that she’s been sour and mean for a while now, probably since the marriage ended. We sit in on Sandy’s introduction of Vincent to her well-heeled parents, who remain civilized but disapprove of their daughter marrying down. We learn the touching story of how Rocco and Marina got together. And most importantly, we witness Rocco being forced to protect his family, which puts him on the hit list of stone-cold career criminal Lefty (Murray).