Proof positive that nowadays they’ll make a sequel to anything, no matter how putrid the original—but then didn’t “The Hangover” already demonstrate that? The first “Hot Tub Time Machine” was dreadful, a 99-minute avalanche of coarseness, raunchy gags and scatological pseudo-humor aimed at the lowest conceivable level. This follow-up, again directed without style by Steve Pink, offers more of the same except that John Cusack, one of the original ensemble, passed this time around and is replaced by Adam Scott as his character’s son. Even though his career isn’t exactly thriving at the moment, his decision shows that Cusack still retains some discrimination in his choice of projects; Scott, not so much.

The script by Josh Heald begins with a prologue showing the effect the trip back to 1980 in the first picture has had on three of the four travelers (Cusack’s insurance salesman Adam having disappeared). Disgusting Lou (Rob Corddry) used revelations about technological advancement to found Lougle (ha, ha!) and live like an over-the-hill rock star. Erstwhile pet-groomer Nick (Craig Robinson) is able to fulfill his dream of a singing career by stealing songs that haven’t been written yet and performing them himself. Lou’s nebbish of a son Jacob (Clark Duke), on the other hand, apparently hasn’t used his foreknowledge at all, still serving as his father’s footstool butler.

When Lou is shot in the groin by an unknown assailant—understandably, one must add, given his loathsome character—Nick and Jacob take him to the first film’s hot tub (which, we’re abruptly informed, has been moved into Lou’s mansion) and go back in time again to save him. But the thing instead sends them into the future—2025, to be precise—where Louis is again whole (and as obnoxious as ever). So they decide to take advantage of the opportunity to find out who attacked him, presuming that doing do will enable the assailant to be deterred somehow, and in the process link up with young Adam (Scott), an incredibly straitlaced guy who joins their mission although he’s to be married the following day (which of course introduces a “Hangover” thread to the plot).

None of this makes the slightest sense in logical terms, of course, but that doesn’t make any difference, because “Hot Tub 2” uses the loony premise simply to present a cascade of gags that are variously gross, misogynistic, homophobic, drug-centric , simply ugly or an unholy combination of the above. Most of them, unfortunately, simply aren’t funny. There’s an occasional moment of real humor—a gag involving a “smart” car that determines to kill Lou (again, an understandable reaction to meeting the guy) has promise, for example, though it’s never developed; and the stream of pop culture references, especially cinematic ones, can bring a slight smile. But when the supposed highlight is a television game show—hosted by Christian Slater, who once upon a time had a career—that involves what amounts to anal rape for laughs, you’re left to wonder just how low American comedy can sink. If this movie is any sort of barometer of contemporary taste, the culture is in deep, deep trouble.

Of course, any movie would have difficulty surviving Corddry at his worst. A thirty-second cameo of him playing this vile character would probably be too much, but here he’s effectively the star, and is frankly insufferable over the long haul. (When the inevitable sentimental bonding between Lou and Jacob occurs, it’s truly awful.) Robinson is more genial but still stiff, and the thought of his being able to make even the best song in the world’s popular strains credulity past the breaking point. Duke gets little to do but look befuddled or angry, while Scott plays the material he’s given (including one of those dismal drugged-out sequences that includes lots of bizarrely distorted visuals) as well as he can, but the material is all so terrible that his effort is in vain. Jason Jones shows up as an apparent replacement for Crispin Glover from the original and gets a good deal of screen time, but to little effect, and Chevy Chase reprises his handyman cameo, looking understandably lost and bored. All the women in the cast are poorly used, and while the production quality isn’t very good, it’s certainly better than the screenplay deserves.

It’s difficult to imagine a movie more determinedly vulgar and crass than this, or one more likely to evoke groans of disgust than gales of laughter. But wait a few weeks, and something even worse will probably come along. Those are the times we live in.