Theatre: But where's `Waterloo'?

Mamma Mia!

Prince Edward, London

Hamlet

Young Vic, London

Roberto Zucco

Barbican, London

Hold on to your memories: rather than jogging them, the "New Musical Based on the Songs of Abba" could well trample all over them. If you like dancing in a haze of personal, time-and-place-specific nostalgia, the experience may take the sheen off Abba Gold.

The plot could have been computer-generated: take the song-titles of Abba's vast output and shuffle for optimum segue potential. ("Bang-a- Boomerang" didn't stand a chance.) Sophie is 21, lives on a sunny, carefree Greek island and is soon to be married (that's "I Do, I Do, I Do" sorted). She wants to know the identity of her father ("I Have a Dream") and secretly invites three suspects to her wedding.

Meanwhile, at her taverna, Sophie's mother Donna (Siobhan McCarthy) works all night and works all day to pay the bills she has to pay. Then the three unwitting "fathers" turn up and surprise Donna (""). Four songs down, 20 to go ... they can't keep up this corny contrivance, surely?

But they do. When writer Catherine Johnson's remarkable literal-mindedness can't encompass "Dancing Queen" or "Super Trouper" - no chance of a surprise call from Glasgow? - she calls on Rosie and Tanya, Donna's old showbiz muckers, to relive their cabaret days. There's a hairbrush-as-mike dance- round-the-bedroom pastiche and a satin'n'platforms hen-night revival. Maybe it's the fault of Bjorn Again, Muriel's Wedding and Priscilla, but the rest of the songs, sung in Nineties civvies, were always going to be dowdy imitations in comparison to the Seventies send-ups.

is as good-heartedly cheesy as Abba - inadvertently or not - ever were. But it often surpasses them by being both ironic and idiotic at the same time. Director Phyllida Lloyd builds up a lot of nudge-nudge wink-wink cheekiness prior to each shoe-horned song, milked by the great comic timing of Jenny Galloway as Rosie. But the knowingness is uneven and the script groans under the weight of its double entendres.

As Sophie, West End debutant Lisa Stokke plays her with a fresh-faced naturalness that's at odds with the exaggeration around her. But this faux-naivete is put to good use in a trippy dream sequence, when she's manhandled by a fluorescent chorus line of blokes in life-jackets and flippers and girls in elbow-length Marigolds and swimming caps.

Such surreal silliness aside, is counterproductive as a crowd- pleasing tribute to Abba's music. The cast are all fine singers and Siobhan McCarthy is excellent, particularly in a belting rendition of "The Winner Takes It All", twisted to make her the valiant victor rather than downtrodden sap. In another proto-feminist turn, "Does Your Mother Know" is sung by the AbFab-esque man-eater Tanya (Louise Plowright) to a young stud. But the grandeur of the original music is sacrificed for a synthesised backing tape, the harmonies are rarely sweet, and the perfect pop songs are mangled in their makeover as show-tunes.

But it's harmless and enjoyable and, as their curtain-calls confirmed, it has the input and bearded blessing of Bjorn and Benny. So, thank you for the music - and the first musical of the new millennium. Just think of the options in decades to come: "Wild Boys - Based on the Songs of Duran Duran", set on a post-apocalyptic "Planet Earth" where everyone's "Hungry Like the Wolf"? Or "Bad Boys - Based on the Songs of Wham!", in which "Young Guns" are having fun at "Club Tropicana"?

Ben Elton and Shakespeare may appear to have little in common. But in the Young Vic/Theatre Royal Plymouth's Hamlet, director Laurence Boswell injects some of the sharp-edged style and pace which made his production of Popcorn so watchable. The traverse stage-set, designed by Es Devlin, is minimalist - two black, wooden platforms, connected or distanced by a retractable central aisle. The props are minimal, the lighting has a stark clarity and the 20th-century monochrome costumes are unfussily idiosyncratic. All of it focuses and defines Paul Rhys's understated but flawlessly realised messed-up young man.

Rhys is a revelation. Whether being a weeping student in grey greatcoat and boots, or a frantic psychotic in white pyjama pants, he keeps his lean face open but watchful. His eyes flicker, his fingers twitch, his mouth quivers. The tics are almost imperceptible, but they are unrelenting.

As a result, his madness is unaffectedly credible. At the end of Act Two, he yells that he "can say nothing", pounds his head with open palms at his lack of gall, and beats the syllables of "vengeance" upon his chest; and still there is a sense of latent, resistant control.

The same perception binds the rest of the cast under Boswell's fluid direction. As Ophelia, Megan Dodds's porcelain features and calm disposition are muddied by grief and pain; Suzanne Bertish's Gertrude is centred and strong; and Robin Soans's Polonius is a fastidious foil to Rhys's cynicism. The only jarring, if inventive, portrayal is the ghost of Hamlet's father; a white knight, with silver visor and gauntlets, who emerges on concealed stilts to spooky music and dry ice. It was certainly striking, but a little more Star Wars than spirit walks.

Roberto Zucco is based on the story of a real-life serial killer. This disturbing, disaffected play by the French playwright Bernard-Marie Koltes was finished just before he died of Aids in 1989. There's no method in Roberto Zucco's madness. Zucco (Zubin Varla) has killed his father. He escapes from prison, and goes on a spree that's both psychotic and apathetic: his mother, a detective and a teenage boy are killed and a 15-year-old girl is raped. Koltes's characters talk of "sheer evil", but Koltes resists such an excusable moral. Zucco has simply lost his mind in a dysfunctional society. He passes silently through an underworld of pimps and thugs, and holds centre-stage as a voyeuristic crowd treat the sight of a woman with a gun to her head as interactive entertainment. It's a caustic vision. But Varla holds it together, while Zucco impassively falls apart.

`': Prince Edward, W1 (0171 447 5400) to September. `Hamlet': Young Vic, SE1 (0171 928 6363) to 15 May. `Roberto Zucco': The Pit, EC2 (0171 638 8891) in rep.

Robert Butler returns next week.