“Punch-Drunk Love” is a bizarre follow-up in many ways to Paul Thomas Anderson’s opus “Magnolia.” Anderson’s previous films ranged from tight presentations like the oft-forgotten “Hard Eight” to the bizarre and meandering in “Boogie Nights,” but his most recent effort is hardly a compromise.

In fact, it had created a buzz in Hollywood for quite some time, particularly when Anderson actually joined the writing crew at “Saturday Night Live” in an attempt to prepare for writing a film featuring Adam Sandler. Considering that every critic had scrapped Sandler after “The Wedding Singer” and Sandler’s ever-reliable fans had stayed away in droves from “Little Nicky,” when Anderson announced his plans, it seemed like a final death knell for all involved.

While most Sandler films could simply be reduced to a one-sentence plot line like, “Idiot rich kid goes back to elementary school to prove he can inherit his father’s business,” “Punch-Drunk Love” doesn’t quite fit the formula. One paragraph couldn’t even explain what a harmonium, pudding, frequent-flyer miles, novelty plungers, a faux velvet blue suit and phone sex have to do with each other. This is how “Punch-Drunk Love” hits the mark.

If there’s anything concise to say about the film, it’s that Sandler plays Barry Egan, a novelty plunger salesman with seven abusive sisters, who falls for Lena Leonard, played by Emily Watson. He isn’t even far from familiar territory, as he will occasionally burst into spurts of violent comic rage, destroying a restaurant bathroom and shattering his sister’s glass doors, but his motivation seems to be deep-rooted. At times, Barry seems closer to a raging Woody Allen than to Adam Sandler.

His trouble starts with a late-night call to a phone-sex line, where he reluctantly gives his credit card information and address to an operator, only to find it too awkward to go through. The next morning, he gets a call from the girl, who asks for money and blackmails him. Lena, a co-worker of one of Egan’s sisters, develops an attraction for him, despite his random behavior and seeming indifference to her.

Meanwhile, Barry is in the middle of a master plan, stockpiling Healthy Choice pudding in order to earn frequent-flyer miles so that he can go wherever he wants at a moment’s notice. The miles take on a more practical purpose when the phone-sex operator sends a trio of brothers to harass Barry until he pays her the money she wants.

From there, Barry and Lena travel separately to Hawaii and begin a romance of sorts, but upon their return, are both attacked by the brothers chasing Egan for Dean Trumbell, played with raging brilliance by Anderson staple Phillip Seymour Hoffman. From there on, the plot ties a few loose ends together, and dares to leave many open-ended.

It is a fair indicator to the complexity of this film that it takes three paragraphs to provide a plot summary that’s grossly insufficient in comparison to the film, which runs only 97 minutes. In a sense, it could count as a romantic comedy, though it definitely pushes the definition of both romance and comedy. There are laughs, but they’re more laughs of discomfort as Barry loses control.

While Sandler lets his character lose control, the direction is superb and Anderson manages to rein this insanity into a character that is so pathetic that he borders on sympathetic. When he is forced to lie to would-be customers and even his phone-sex vixen about the success of his business, a struggling warehouse for plungers with novelty tops, it explains a lot about why he would take in a harmonium, bizarrely dropped off in the street like so many frogs in “Magnolia.” He is desperate to express himself in some way, but when he finds it, he just can’t own up to it.

The script is masterful, mostly because it can tell the difference between what you expect leading men to say, and what a man as unstable as Barry would say. There are several times, particularly in a final plea from Barry to Lena, that the script borders on lines like “You had me from hello” that will be quoted for years to come. Instead, they just border on it and sidestep them altogether, leaving the viewer to wonder why the script didn’t play that angle and turn Barry into a lovable loser. Instead, he’s a loser that the viewer isn’t certain to like.

By the time this film reaches its open-ended conclusion, it’s more likely than not that most people will leave the theater relatively punch-drunk. Many will love it, many will denounce it as pretentious and everyone else will wander for weeks if they liked it or not. Paul Thomas Anderson’s fans aren’t certain to love it, but it’s that sort of edginess and uncertainty that makes it so impressive.