FILM / Search for oil strikes gold: Lorenzo's Oil (12); Honeymoon in Vegas (12); Under Siege (15); Romper Stomper (18); Leon the Pig Farmer (15)

STRIDENT but sincere, Lorenzo's Oil is an illness movie that jerks thoughts as well as tears. Early on we see the ailing Lorenzo, aged five, paraded before a lecture theatre of medical students. Tier upon tier of starchy white uniforms stare at him. He stands on the stage, alone save for a doctor asking him to take a few paces. His walk is tortured and unbalanced. When he calls to his mother, his speech is a faltering blur. His head, with its few wisps of hair, resembles a coconut. At first you're unsettled by this exploitation, but you come to believe the end justifies the means: Lorenzo's exposure may advance science; scruples won't. The movie is the same, worrying you, and then winning you over. It's about the uneasy relationship between suffering and science.

It tells the true story of a Maryland couple, Augusto and Michaela Odone (Nick Nolte and Susan Sarandon), and their discovery, in defiance of establishment medicine, of a treatment for the degenerative disease adrenoleukodystrophy (ALD), which afflicts their son Lorenzo. The film feels more like a detective story than a three-hanky job. Faced with Lorenzo's terminal illness, the Odones don't lie down and let him die, they piece together all they can about his little-known disorder. We follow them through the mazy backstreets of scientific research, sharing their exhilarating discoveries.

The film roots for the Odones, but it's fair. Their hunt for a cure is implacable and at times unnerving, leading to clashes with waverers. The counter-argument is always aired, whether it's doctors warning against treatment with untested oil or parents of other ALD children trusting in 'the solemn sanctity of science'. At worst the opposition seems tiresomely myopic. Sometimes it's hard not to sympathise, as with a nurse sacked for not attending to Lo renzo's mind, who questions whether he has one. She and we are proved wrong, but the film's spirit is inquiring rather than vindictive.

George Miller, who mastered the action movie in the Mad Max trilogy, does a fine job directing inaction. He even makes drama out of library books. When Augusto first looks up the disease in a medical encyclopaedia, the screen swims with print, mimicking the father's mind reeling at his son's mournful prognosis: 'blind . . . dementia . . . quadroplegia . . . spastic . . . deaf . . . mute . . . coma . . .' It's one of the most moving scenes in the film, and it's shot from inside Augusto's head.

Susan Sarandon's Michaela dominates the film. Her sorrow is compounded by being the carrier of the disease. Ashen, unyielding, her huge eyes filled with misery, she doesn't care what people think of her - even the audience. 'How can I enjoy anything, when he enjoys nothing?' she asks. They make a good advertisement for marriage, Michaela's resolution knitting with Augusto's ingenuity. Nick Nolte portrays a practical intelligence tackling a problem. You wonder if his Italian accent will last the course, but by the end it seems of a piece with his character - an extrovert hemmed in by a crisis.

Peter Ustinov, as the ALD authority, Dr Nikolais, is the voice of medicine: humane, rational, but a touch complacent. Ustinov's leaden deliberation is a good foil for the Odones' febrile curiosity. There's also an unusual cameo, as himself, from Don Suddaby, the London chemist who made up the oil which the Odones identified as the treatment for ALD. His blunt tones ground the film in the real world. The exposition can be heavy-handed, with pace sacrificed to clarity. But normal artistic criteria don't quite apply. It's an inspiring story well told.

In his last movie, The Freshman, Andrew Bergman lured Marlon Brando out of retirement. For Honeymoon in Vegas, he's assembled a hall of fame on the soundtrack: Bryan Ferry, Billy Joel, Jeff Beck, Willie Nelson and Bono, all covering old Elvis numbers. Whatever magnetises the megastars, it's unlikely to be Bergman's scripts. Seldom more than one-joke wonders, they tend to play better in the pitch than on the screen - perhaps the secret of his pulling power. This one is about a man who loses his fiancee at poker. It's only for a weekend, but that's long enough to exhaust Bergman's wit. There's also the added joke of having Las Vegas overrun by an Elvis convention, affording some dubious laughs at Elvises who are Japanese or black.

The best thing in the film is Nicolas Cage, who gives a spin to the most tired lines. With his rasping voice and heavy-lidded eyes, he's a wilder Jimmy Stewart. The humour lies in the contrast between his macho, hirsute body and his fragile emotions. When he's duped into thinking he's a high-roller and raises the poker stakes, he feigns nonchalance but can't suppress a childish glee. He begins by dithering over whether to marry his girlfriend (Sarah Jessica Parker) - probably because she talks like a psychobabble manual - and ends taking the plunge, sky-diving on Vegas in an Elvis costume. He's always been the young actor who seemed most Kingly.

In Under Siege Steven Seagal plays the heroic cook of a hijacked nuclear battleship. He's the last line of defence against a catastrophe so horrific it doesn't bear thinking about. Half an hour to save the Western world and whip up a bouillabaisse. The film tries hard to be Die Hard. It doesn't succeed, because the plot gives up halfway in favour of fireworks, and the dice are loaded against the villains. They're a bunch of bungling maniacs, lacking Alan Rickman's sardonic intelligence. Tommy Lee Jones and Gary Busey look as if they know this, going over the top, and then a lot further.

Seagal himself has none of Bruce Willis's cursing self-doubt. With his bronzed, rectangular head he looks like a Frink sculpture, and is about as animated. Fresh out of the Roger Moore school of acting, he registers emotion by twitching his Adam's apple, but his martial arts background lends beef to his gun-toting gourmet. Erika Eleniak, from Baywatch, jumps out of a cake wearing half a bikini to play the damsel in distress. The camera stalks and fondles her. The film was America's fourth highest grosser last year.

Recent weeks have seen a succession of violent movies, each more brutish than the last. Romper Stomper is the apogee - or nadir. You may not want to view it at all, if you're offended by neo-Nazism, racial violence, gang warfare, arson, murder, brutal sex, swearing, Mein Kampf, or beatings with billiard cues and bicycle chains. The film is a portrait of the pack mentality and mindless violence of a group of skinheads, with a romantic rivalry thrown in. It's shot in a wan blue light, somewhere between Quadrophenia and a Levi's ad. It's oddly derivative - of everything from My Own Private Idaho to A Clockwork Orange - and its desultory world leaves us unmoved.

After Alan Bennett's A Private Function, which was about war-time pig theft, the British film industry now presents Leon the Pig Farmer. While the rest of the world churns out splatter movies, we make trotter films. The film wants to be a north London Woody Allen. When the Jewish Leon discovers that owing to a quirk of artificial insemination he's in fact the son of a Yorkshire pig farmer, the gags turn cross- cultural and there's a whiff of half-baked metaphor. But there are enough laughs to suggest that writer-director Gary Sinyor will work on budgets bigger than pounds 160,000.

'Lorenzo's Oil' (12): Empire Leics Sq (240 7200), MGMs Trocadero (434 0032), Fulham Rd (373 6990), Whiteleys (792 3324). 'Honeymoon in Vegas' (12): MGMs Oxford St (636 0310), Chelsea (352 5096). 'Under Siege' (15): Empire and gen release. 'Romper Stomper' (18): Prince Charles (437 8181). 'Leon the Pig Farmer' (15): MGMs Trocadero, Camden Parkway (267 7034), Everyman (435 1525), Odeon Kensington (371 3166), Clapham Picture House (498 3324). All nos 071.