Why did he waste himself in movies as a repellent nasty, hotheaded detective first grade, parole officer or comic father? Robert De Niro now comes back to his early star-making unpleasant yet compelling Travis Bickle-Jake La Motta mode in Being Flynn. His alcoholic, arrogant, racist, homophobic, ex-con and potentially dangerous runaway-absentee husband-father Jonathan R. Flynn is non-stop over-the-top. In contrast, his feckless, weak-willed, guilt-ridden son Nick (Paul Dano) relies on boyish charm to cover a bland non-existence. But, both united by writer’s itch and a susceptibility to addiction, sire and son need to be extreme, so that both can admit the truth yet falsity of dad’s “You are me! I made you!” even though final frames too facilely reverse that through Inez (Kelly J. McCreary) at a symbolic book reading.

Inez actually appears in the Nick Flynn memoir continuation after Another Bulls__t Night in Suck City, on which the film is based, and the love interest Denise (Olivia Thirlby) who wises Nick up is a screen addition to the based-on-real-people autobiographical variant.

Author Flynn spent seven years on the first, 1997 memoir, and thirty drafts over another seven went into director/co-producer Paul Weitz’ screenplay. Too much is voiceover from the two male protagonists, overkill telling of what should be shown and, in fact, is pretty much revealed in dialogue and visuals, anyway. De Niro’s memorable performances have been as loner loonies with no empathy or consideration for others and whose grand delusions are magnificently unsubtle. Despite manic anger and a baseball bat, nail-studded club, pistols and knives, the dementia now appears less physical than before. Nor can nuance be found in his unexpected remorse, or just self-pity, at having walked out on wife Jody (Julianne Moore) and son (Liam Broggy as child Nick).

Self-centered irresponsibility continues to the present day, the prerogative he assumes as the great American author to stand alongside Mark Twain and J.D. Salinger. Actually having written the first of numerous planned volumes of the magnum opus, he boasts of the prescient few who have faith in him, the rich friends begging for his presence at their Florida mansions.

SPOILER ALERT

Retiring Nick, too, is shadowed by his suicide mother, who left a note before turning a pistol on herself and who he fears was driven to final despair by an unfinished early story of his.

Not aggressively self-trumpeting like the father he has not heard from in eighteen years, Nick harbors family literary ambitions, finally in the direction of short poems rather than epic pies in the skies. His airhostess wife throws him out for zero literary or bread-winning accomplishment, but he finds digs in a cavernous multi-storey former dance club, as films still give space- and affordability-challenged New Yorkers living quarters to die or kill for. His coke-dealing black and fey gay white roommates are the very types father Jonathan rants against.

Impossible as a tenant, that father gets evicted and, turned down by others, locates son Nick through, he says, the telephone book and without so much as a thank-you has the three young roommates move his possessions to a storage unit and then disappears again. Through semi-girlfriend Denise, Nick is working at homeless shelter Harbor Street Inn, whose employees, including Denise and Joy (real-life author Flynn’s wife Lili Taylor), and homeless residents are humorously but realistically and sympathetically imagined.

A physically and mentally downspiraling Jonathan reenters his son’s life, showing up for admission to the shelter but causing problems with his drinking and disruptive behavior. Social drinker Nick is driven to heavy drinking himself and to drugs and dependency, even if more or less still functioning.

The meeting of past and present – flashbacks -- and of father and son; the coming to grips with ghosts, guilts and resentments; and the learning of relative tolerance and acceptance, are, if not precisely telegraphed, then givens from early on, for the tragic tone is clearly absent. Reactions to the film will depend on acceptance of the two men’s performances, which are good despite some contrivances in circumstances that surround them.

(Released by Focus Features and rated “R” for language throughout, some sexual content, drug use and brief nudity.)