Wow, does “Zoom” ever suck. Wow, wow, wow. One expects very little from a film that is obviously a rip-off of something else (“Sky High,” in this case), that is released without any advance screenings, and that comes from Peter Hewitt, who one recalls was the director of “Garfield.” But one could not have anticipated just how inept, unfunny and embarrassing “Zoom” would be. It surpasses all expectations.

Based quite loosely on Jason Lethcoe’s “Zoom’s Academy” books, “Zoom” is about the government’s efforts to prepare for the imminent return of a supervillain called Concussion. He was dispatched to another dimension by a squad of superheroes some 30 years ago; one of those heroes was his brother, Zoom, now mostly superpower-less and living in obscurity as Jack Shepard (Tim Allen). The army types, led by warmongering Gen. Larraby (a blustery Rip Torn), drag Jack back to Area 52, where his services are needed.

But he’s not supposed to fight the bad guy. They want him to train a new Zenith Patrol (as it was called), choosing four kids who have been displaying unusual powers and helping them to refine them. Jack is soured on the whole “superhero” thing, but he likes the $500,000 the government’s going to pay him to play Professor X to the wannabe X-Men.

The kids have Fantastic Four-ish abilities. From youngest to oldest they are: Cindy (Ryan Newman), with super-strength; Tucker (Spencer Breslin), who can inflate and stretch any part of his body to any size; telekinetic Summer (Kate Mara); and invisible boy Dylan (Michael Cassidy). The latter two are teenagers, so they’ll be falling in love. Young Tucker gets to be the butt of fat jokes, and precious li’l Cindy is so G.D. cute you’ll want to deep-fry her and dip her in cocktail sauce.

Once everything’s been set up, the film immediately forgets what it was doing and wanders off. Jack is supposed to stop being selfish and start caring about the kids and the Zenith program, while the kids are supposed to come to terms with their uniqueness and embrace their powers. Neither of these things really happens, at least not in front of us. Instead we get random, unnecessary, illogical bits such as:

– Jack and the kids take an alien spaceship out for a joyride to the nearest Wendy’s, where the drive-thru operator is Squiggy from “Laverne & Shirley.”

– The kids lock the egghead scientist Dr. Grant (Chevy Chase) in a weather-simulation room. One of the “weather” options, along with rain and snow, is an artificial skunk, complete with stinky spray. Why would you include that in a weather-simulation room? What possible scenario might the superheroes find themselves in where knowledge of skunk-repellant techniques is vital?

– A research assistant named Marsha Holloway (Courteney Cox) keeps slipping and falling, each time less funny than the last. She meets Jack, still in his civilian life, by pretending to faint outside the racing shop he owns. Then the government guys swoop in and bring him to Area 52. It is never explained why the subterfuge was necessary, since they all could have just walked into the shop and talked to Jack.

– Jack and the kids play an extemporaneous game of softball in the lab. It is not funny, and it does not advance the plot. It probably took a day to shoot and cost $1 million.

– There are approximately one million instances in which Cindy picks up something heavy and throws it. I’m guessing one million because I lost count after 998,482.

The script (by “Mousehunt’s” Adam Rifkin and “Elf’s” David Berenbaum) frequently has characters saying lines that are clearly meant to be jokes. They occur immediately after set-ups; they are spoken in a broad “I’m making a joke!” tone. And yet they are not funny. They are often puzzling and awkward, as if taken from the film’s rough draft rather than the final product. They are the sort of gags written by high school students for Skit Night. Even the OUTTAKES for the movie, played over the closing credits, aren’t funny. And the outtakes are ALWAYS funny!

It does not help that nearly every moment of the film is punctuated by Christophe Beck’s whimsical-bumbly-hokey musical score. It underlines and italicizes every joke, which has the effect of ruining the joke altogether.

Tim Allen is game for anything, of course, as evidenced by his indentured servitude to Disney, and his performance here, half-hearted though it may be, is not a problem. But seeing Courteney Cox flop-sweating through her farcical role as Miss Holloway is uncomfortable, and watching the once-great Chevy Chase reduced to this bug-eyed buffoonery just flat-out embarrassed me, like watching an old man crap his pants at the grocery store. I felt bad for the guy, and I felt ashamed for having seen it.

There are two easy ways to tell when a comedy is desperate. One is when there’s a character who falls down a lot. (Check.) The other is when there is gratuitous grossness and/or characters being covered in vile substances. On that point I will merely observe that two of the rejected junior superheroes are a boy with thunderous flatulence and a boy who can blow boulder-sized snot bubbles. “Zoom,” ladies and gentlemen! I give you “Zoom.”

F (1 hr., 23 min.; PG, the standard flatulence and other crude humor.)