A revisionist version of Matthew McConaughey's last romantic comedy, 2003's "How to Lose a Guy a 10 Days," "Failure to Launch" swaps Kate Hudson for the vivacious Sarah Jessica Parker (2005's "The Family Stone") while keeping the whole pretending-to-fall-in-love- before-actually-falling-in-love angle. Yep, it's that ancient plot where a relationship begins as a bet or job before becoming the genuine article, and yes, there is that age-old scene where the unbeknownst party discovers the truth and angrily confronts the love interest who—gasp!—really does care for him/her after all. Keeping in mind that there is a formula to be followed in practically any studio romantic comedy, "Failure to Launch" is a pretty good one—half the time. When the stars, including a standout supporting cast, aren't charming the viewer, the film is busy shooting itself in the foot. Taking the idea of truth in advertising to an entirely new level, there's even a scene where a character is accidentally shot in the foot.

Tripp (Matthew McConaughey) is a handsome 35-year-old bachelor who still happily lives at home with his parents, Sue (Kathy Bates) and Al (Terry Bradshaw), and has no intention of ever leaving. Paula (Sarah Jessica Parker) is an interventionist whose job it is to get long-grown men out of the nest by way of making them fall for her and becoming more independent in the process. Tripp becomes Paula's latest subject when Sue and Al, ready to see their son fly on his own, hire her, but it's not quite as easy-breezy this time around. Used to keeping her distance and not becoming emotionally involved in her non-sexual conquests, Paula is reluctant to admit that she starts having feelings for Tripp, even in his imperfections. What chance do these two lost souls have, though, when their relationship has been built on a lie?

Haphazardly directed by Tom Dey (2002's "Showtime"), "Failure to Launch" is technically one of the messiest studio releases in months. The editing has been done with a chainsaw, cutting erratically between too many extreme close-ups and the shots lacking in flow and continuity. Characters speak without their lips moving, or their dialogue does not match the movement of their mouths, on more occasions than can be counted on two hands. Oftentimes it appears as if free reign of a big-budget star vehicle has gone to someone who has never actually picked up a camera before, but is happy to be there all the same. That Dey has made several pictures before this one is mind-boggling; hasn't he learned anything from those past experiences?

Editing and dubbing issues aside, "Failure to Launch" works on the occasions when the actors are left to strut their stuff and radiate their natural charisma. All involved are strong enough to withhold some scripting problems, but no one involved would be able to sell the ways in which the movie jumps the gun. First, the good: as Tripp and Paula, Matthew McConaughey and Sarah Jessica Parker are a casually amiable pair; though there aren't exactly fireworks between these two, they work easily together and are both deserving of a happy ending. This is particularly surprising considering Paula is asked to do some despicable things behind the back of Tripp, and is more or less a prostitute-for-hire. Parker classes the role up and still makes it work because she has tackled the character from the standpoint that Paula is leading a lonely, empty life and mistakenly believes what she does for a living is a virtuous public service. The premise of a man in his mid-thirties still living at home is also handled maturely and realistically. The key is that the film does not judge what is or isn't right, but simply observes that there comes a time when a man should be willing to at least make his own breakfast and do his own laundry.

Despite being sturdy enough leads—in a race, Parker would probably narrowly beat McConaughey because of the complex moralistic quandary Paula finds herself in—it is the supporting players who steal their spotlight. As Tripp's mother, Kathy Bates (2005's "Rumor Has It...") gets the film's most touching scene—a heart-to-heart with Tripp where she expresses her fears of rekindling a happy relationship with his father when it's been so long since the two of them have shared a life alone together. As Tripp's dad, former NFL quarterback Terry Bradshaw is amazingly at ease in front of the camera, even when called upon to show his naked backside for an inordinately long amount of time.

Best of the lot is Zooey Deschanel (2005's "The Hitchhiker's Guide to the Galaxy"), graceful and quirky and bizarrely delightful as Paula's best friend and roommate Kit. What could have been a stock part is anything but in the hands of Deschanel, whose dry sense of humor is perfect for a character who constantly seems on the verge of a nervous breakdown. A subplot in which she plans the murder of a mockingbird who incessantly chirps outside her bedroom window has zilch to do with the rest of the story, but gets the picture's biggest laughs.

Where "Failure to Launch" goes wrong is twofold. First, the over-the-top physical humor as Tripp is attacked again and again by a parade of psychotic animals—a chipmunk, a dolphin, a lizard, etc.—is unnecessary, distracting and painfully unfunny. Second, the love story that is supposed to be the central plot thread remains too underdeveloped to hold much weight. So much time is spent with other characters and feuding storylines that their own romance plays like an afterthought. This might have been forgiven if it weren't for the biggest sin of all: a climax that trades in the chance to be thoughtful and sweet for a sub-level sitcom idea where Tripp and Paula's reconciliation is viewed by the rest of the characters and strangers alike via strategically placed webcams. This potentially heartfelt sequence is destroyed by a smarmy, mugging idiocy that destroys what momentum these two possible soulmates had been building up throughout the film. As for the careless discrepancies involving the film's setting—dolphins in the waters around Baltimore, I think not—the less said, the better.

"Failure to Launch" is airy and sporadically enjoyable just as it is also dumbed-down and abysmally edited for half its running length for no apparent reason. Individual moments ignite effective sparks—for example, the now-archaic confrontation scene after Tripp learns the truth is deemed fresh again here, stinging with a very authentic emotional pain that is rarely approached in such light cinematic confections—but they are constantly vying for attention against sloppy, aimless scenes that bring things to a crashing halt. "Failure to Launch," like "How to Lose a Guy a 10 Days," is more ambitious than it is auspicious. They both, alas, are finally done in by a script with an IQ level noticeably lower than that of their savvy cast members.