Punch-Drunk Love (15)<br></br>Two Weeks Notice (12A)

A man sits at a desk. He's wearing a suit and tie and making a business enquiry over the phone, so he must be in an office. Except that he isn't. When he gets up, we see that his desk is tucked into the corner of a half-empty warehouse. He flings up the roller door and the light is so dazzling that it refracts into blobs of colour that float across the screen.

He wanders outside to glance at the early morning traffic. Suddenly a van flips off the tarmac and tumbles end over end down the street. Just as suddenly a taxi skids to a halt, a pair of hands reaches out, a harmonium is dumped in front of him, and the taxi speeds off. Where the taxi is going is a mystery. Where the film is going is a mystery, too.

From that opening onwards, Punch-Drunk Love isn't easy to get to grips with. It can be a like a Warner Bros cartoon, a silent movie and an expressionist thriller, but what it reminded me of most was a short film. It has the same quirkiness and richness as you get when a director has just a few minutes and a low budget to show what he or she can do – the same restless experimenting with lighting, sound levels, music and narrative.

True, Punch-Drunk Love is 90 minutes long, but it was written and directed by Paul Thomas Anderson, and his two most recent films lasted two-and-a-half hours and three hours respectively. For him, 90 minutes counts as short.

In Boogie Nights and Magnolia, both released while he was in his twenties, Anderson steered dozens of characters through dozens of locations, establishing himself as the heir to Robert Altman's throne – the Crown Prince of Sprawling, Interlocking Stories About Soulful, Imperfect Characters. After these momentous logistical exercises, you can't blame him for wanting to ease off and play around – or for wanting to keep the camera on one man for almost all of the film. That man is Barry Egan (Adam Sandler). He sells novelty toilet plungers ("fungers") in Los Angeles. He's withdrawn and assiduous, and prone to extreme

moodswings, probably because his seven sisters have been belittling him non-stop since he was born: he can't even use the word "chat" without their heaping abuse on him for being pretentious. He's also being blackmailed by a Mormon phone-sex operator, and he's got a scam in mind involving the complimentary air miles given away with Healthy Choice chocolate mousse. Then, as abruptly as the harmonium was deposited outside his warehouse, an eager, enigmatic Englishwoman, Lena Leonard (Emily Watson), arrives in his life. The only trace of Altman's influence is the prominent use of "He Needs Me", a song trilled by Shelley Duvall's Olive Oyl in his 1980 live-action flick Popeye.

If you had to categorise Punch-Drunk Love, you'd call it a romantic comedy, but it's much more skewed and scary than that implies. Come to think of it, it's much more romantic and comic than that implies, too. Almost every scene has enough in it to be a mini-movie, and almost every shot is so wittily framed that it could be a poster. At times this intensity can be wearing.

One sequence has an avant-garde percussion soundtrack of thumps, clangs, crunches and bleeps, and after a couple of minutes it does feel rather like having a saucepan over your head while someone bashes it repeatedly with a wooden spoon. Mostly, though, Anderson's determination to keep the audience on its toes is exhilarating, because you genuinely don't know what's going to happen from one moment to the next. At any second, a chair might collapse or a fork-lift truck might crash into a wall or a well-known actor whom you weren't expecting to see might walk on screen. Punch-Drunk Love starts with absolutely no credits or titles, so I won't betray it by telling you who that well-known actor is.

The last film to be as highly concentrated as this was Amelie – which was written, co-incidentally, for Emily Watson before she pulled out and handed the lead role, and movie stardom, to Audrey Tautou. But Punch-Drunk Love isn't all about exaggeration and artifice; it's filled with rough-and-ready humanity, too. Anderson seems to take pride in emphasising the lines and the sweat on Sandler and Watson's faces. More than once, someone asks Barry why he's doing something – why, for instance, he's wearing a suit of bright blue favoured by tour guides and air hostesses, only for him to reply, "I don't know." It's strangely refreshing. In films, people always know why they're doing what they're doing, whereas in Punch-Drunk Love they're uncertain. They're just hoping that no one will ask.

Watson is alluring as Lena, who has a predatory hunger for everything that is most demented about Barry. But it's Sandler, as the terrified, struggling, geekish but valorous hero, who is Anderson's smartest casting. Some critics have described the role as a departure for Sandler, when in fact it's nothing of the sort. Even in those of his films which are collections of crappy jokes and gloopy sentiment – ie, nearly all of them – his own characters invariably have a childlike dopiness that masks an itchy dissatisfaction and a hair-trigger temper. Anderson has just removed the crappy jokes and the gloop and kept the Sandler persona. It's a lot like Dustin Hoffman's in the 1970s.

Punch-Drunk Love wasn't a hit in America, so it's probable that Sandler will slither back down to his usual level, while Anderson gathers his strength for another three-hour symphony. Treat yourself to Punch-Drunk Love while you can. In most romantic comedies you know that the principals will end up as a couple. In this one you don't know whether they'll end up together or apart, sane or mad, alive or dead.

It's all the more glorious set against this week's other rom-com, Two Weeks Notice. The Muppet-voiced Sandra Bullock, also the producer, casts herself as a liberal legal-aid attorney. She doesn't pay much attention to her hair and clothes at first, so it's only a matter of time before she dolls herself up and is told that she's "absolutely beautiful". Hugh Grant hams it up as a prattish New York property developer who doesn't care about anything except money, so it's only a matter of time before he's the one telling Bullock how absolutely beautiful she is. The happy ending – that's only a matter of time, too.

Now, I realise that Punch-Drunk Love is the exception to the romantic comedy rule. I appreciate that we usually assume that the leads will get around whatever obstacles are strewn in their path, and that the fun is in seeing how they do it. But in Two Weeks Notice there are no obstacles. Within maybe 15 minutes of the lights going down, Bullock is employed as Grant's Girl Friday, and they're larking around like old school pals. Marc Lawrence, the writer-director, distracts us with some nice screwball one-liners, but the supporting characters aren't characters at all, the set-pieces are badly staged, and the story has nowhere to go but down the aisle.

n.barber@independent.co.uk