For a filmgoing public that needed a Shakespeare history play re-titled to avoid its being mistaken for a prequel or sequel, Hamlet 2 flaunts a long list of tasteless comedic box-office types such as troublesome talented teens in need of ego-strokes; an unorthodox inspirational teacher; potty mouths; pratfalls; fun in alcohol and drugs; ethnic slurs and stereotypes; shortsighted authority figures; religion; the conservative right.

Surprise, with pure overkill and an unrealistically Broadway-worthy proscribed high school play out of Grease highlighted by Hair-hippie “Rock Me Sexy Jesus,” this parody of self-parodies pulls it off. Episodic non-stop pile-it-on like much of contemporary humor, it swings from the shallow, gross or cruel, through obvious overdone, to moments of inspiration, not building a thread of laughter so much as starting anew with each mock-pompous voiceover-and-title-introduced “act.”

Once is fine, but I hope Dana Marschz and his pupils are not to be paraded in a 3 and 4 and 5.

Failed as son, breadwinner, alcoholic, actor, author and teacher, Dana (Steve Coogan) is long on gender uncertainty and short on objective brains as the drama instructor at Tucson’s West Mesa High. Led by Octavio Marquez (Joseph Julian Soria), who calls himself Haywood to preface an obscene pun, the overwhelmingly Mexican-American class is uninterested, insulting and foul-mouthed. Epiphany Sellers and gay Rand Posin (Phoebe Strole, Skylar Astin), his two Anglo stars, are leery of Hispanics but worship their teacher and his stage adaptations of Mississippi Burning and Erin Brockovich so awful even the school paper pans them. Unaware he is out of touch, spouting unappreciated lines from screen and stage, he clumsily roller-skates around to save money and cannot see his marriage falling apart.

Ex-“dealer not a pusher” wife Brie (Catherine Keener) gets more lustful than usual when she drinks, which she does often, and professes dislike for their rent-paying boarder Gary (David Arquette), who does more than drive her around from their enviable house. She barely tolerates the Arizona city and her husband’s zany idealism, apologizing for him at the Prickly Pear Fertility Clinic when he goes loudly gushy at the discovery that, soul-sick of Hollywood, Elisabeth Shue (as herself) is working there as a nurse. More in tune with his enthusiasms, the “former” actress agrees to pep talk his class, taking with grace “Who are you?” from the teens.

Director Andrew Fleming and Pam Brady’s script had its germ in character, Dana’s, a man facing middle age and disappointment. Through much rewriting over five years seeking backing, and later in actors’ input and embellishments, the final product emerged piecemeal and added a good amount of its in-your-face political incorrectness for the irreverent fun of it.

Particularly built up, to a winning pitch, is the play-within-the-play, or rather –movie, which converts naysayers and gets a rave from The New York Times and consequently a Great White Way run that justifies, rewards, and couples off the good dreamers.

With the addition of brassy cursing female ACLU lawyer Cricket Feldstein (Amy Poehler), who apologizes that “I married a Jew,” complications along the way to triumph are standard stock-in-trade, some working, others not. You have the typical students’ misgivings and mutual antagonisms before they hop on board, and as usual their parents, shocked by tastelessness or irreligion or, in Octavio’s cultured home (Deborah Chavez, Marco Rodriguez), voicing scholarly artistic objections to mangling literature. The broke school board votes to scrap most liberal arts, anyway, justifying principal Mr. Rocker’s (Marshall Bell) barring the now-committed players and their mentor from gymnasium rehearsal space. When not lacing others’ juice with drugs, the cute Hispanic kids drink underage and as a matter of course pick the new lock in seconds, for the cause célèbre musical is to be protected from killjoys by burly school jocks who also ensure Rocker’s attendance (and conversion).

SPOILER ALERT

The principal, too, has father and sexual orientation issues, which the play makes him recognize and resolve as smoothly as does Dana in the onstage time-traveling Son’s reconciliation with Father. A few stomp out, but the converted stay to sway and stomp, even three Bible-bearing Christian girls set free by the Truth.

At peace with dead dad but otherwise unchanged, Dana enjoys the acclaim that long eluded him, plus a prize in a physically and emotionally compatible girlfriend. Early drafts pointed to a household ménage à trios, deleted but with too many bits left in about Dana’s sexual ambiguity and performance. Indeed, one objects to too much of everything. Subtlety is not a strong point, here or in current movie and TV comedy. But this time it works, with outrageous exuberance to carry it off.

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