How long would it take to count the idiocies in “This Is the End”? Fooled you! Trick question. Numbers don’t go that high. The badness of this smirky, juvenile hard-R comedy is incalculable. This is a movie full of talented people who have entertained me in the past and who, on some level, I genuinely like. And they’re just dreadful.

The premise is promising, a warped take on disaster movies. On the night of a big party attended by half of young Hollywood, earthquakes, fires and horrific forces lay siege to the planet. Seth Rogen, James Franco, Jonah Hill, Jay Baruchel, Danny McBride and Craig Robinson, plus a busload of junior varsity cameo players, are put in mortal peril. Most die comically gruesome deaths. So far, so good.

But it’s all in the doing, and the execution is excruciating. The stars, playing twisted meta-comedy versions of themselves, come across as whiny, selfish blowhards. Yes, the actors are lampooning their profession’s superficiality, but it’s a delicate trick to play an egocentric, drug-addled nitwit and keep the audience charmed.

The plot is haphazard, sparse and repetitive, the gags-to-laughs ratio unforgivably low. Emma Watson appears for a five-minute supporting turn, stirs the pot and vanishes. This is the opposite of ensemble comedy. Every actor seems to be sweating to come up with something funny on the spot. The results are lowbrow, pseudo-risqué and sad. There are, at this late date, Lindsay Lohan jokes.

Rogen, who co-wrote and co-directed this film with Evan Goldberg, has spent the past several years renouncing his early, sentimental Judd Apatow comedies. His output as a writer ranges from the sharp-witted teen farce “Superbad,” to the migraine-inducing superhero flop “Green Hornet,” to “The Watch,” a crass sci-fi comedy about aliens in suburbia that practically dripped monster splatter. This effort recycles ideas from all those films, improving none of them.

In a scattershot movie like this, which gives equal weight to dime-store theology, male-bonding clichés and pee jokes, you take your pleasures where you can. I liked the sound and fury of several comic action scenes. I enjoy Rogen’s lovable schlemiel shtick. I smiled at the childishly awful artworks adorning Franco’s museum-sized mansion. And who among us has not wanted to see Michael Cera impaled by a toppling telephone pole?

The film’s key mistakes are to think that overblown equals funny and loud equals exciting. The misfired punch line is an epic eruption of brimstone and beasties that looks like a stoner’s vision of Gotterdammerung. I’m not going to imply that drugs were involved in the making of this movie, because I have no evidence that was the case. But feel free to judge the bad trip for yourself. “This Is the End” probably won’t end any careers, but it sure won’t help.