The Magazine: Restaurant review - it's an instant London landmark. What it isn't, quite yet, is a restaurant

Strange things can happen to unwary travellers who venture into the park after dark. Unsettling things. They may find themselves perched in a deserted space-station, pecking at mystifying specks of food, while strangers pop up murmuring "Can I introduce you to our bread?". They may end up lurching out into the night, grateful for the comparative safety of an isolated car park. They may have visited The Magazine.

It was never going to be bland, this new restaurant and event space in Kensington Gardens, which wraps around the Serpentine's new Sackler Gallery like a whale's pelvis fused on to a Soviet war memorial. Designed by Zaha Hadid, it's a bold statement of creative intent, a billowing, melting canopy which swoops and soars fantastically, and has about as much interest in blending into the landscape as Grayson Perry.

It's an instant London landmark. What it isn't, quite yet, is a restaurant. The interior is dramatic, but it has a drafty, makeshift feel, like a temporary pavilion at the Venice Biennale or a futuristic expo. "Zaha hasn't finished the cloakroom yet," apologised the manager, as we bundled coats and bags under our wobbly table, rather ruining the effect of all that stark whiteness.

Introductions to the bread complete – the black-pudding loaf with whipped butter is worth meeting, though it doesn't have much small talk – we navigated our way through a menu which could well be an exhibit from the neighbouring gallery space: The Possibility of Japan in the Mind of Someone Eating Pork Scratchings. The list veers randomly from sushi and sashimi to braised pork with crackling, occasionally forcing a collaboration, as in sea trout with unagi, or Black Angus fillet with yakiniku sauce.

The artist behind it is chef Oliver Lange, whom we can safely call a wunderkind, because he is young, German and very successful. He also trained in Japan, and is apparently famous for his sushi, which makes him perfect casting for the Sackler; those arty types love that stuff. If the rest of the meal had been as good as the five little flavour-bombs which began our meal – I didn't catch their names when we were introduced, but they included a dragon roll, mackerel nigiri and something involving white truffle – we would have been very happy.

The rest of the meal, though, passed in a hallucinatory blur of morsels, foams and evanescent mystery tastes. A couple of the dishes came into focus; a starter of pork cheeks, braised to a sweet, dark shine on a slick of puréed Jerusalem artichoke, and garnished with huge curls of puffy pork scratchings. And a terrific, suede-soft slab of beef fillet in a belting umami-rich sauce, with edamame beans, Swiss chard and pickled mushrooms, like a Japanese take on Sunday dinner.

But others were incoherent, hobbled by over-complication or downright weirdness. Actively nasty was a kind of veggie twist on coronation chicken – slices of griddled cauliflower, charred at the tips, the flesh acidly al dente, in a mildly curried cream sauce. "This is... not good," said my friend James, "in a way you rarely get in a restaurant."

Constant interruptions from the sweet but maniacally effusive waiters began to turn the meal into an ordeal. When one popped out from behind the giant stiletto-shaped pillar next to us to respond to an idle speculation about what the surprise in the 'chocolate surprise' might be, I almost let out a girlish shriek.

This vast room would be first-date territory only for a pair of astronauts looking to experience the effects of atmosphereless space. As the blippy ambient soundtrack rose in volume, we began to feel like we were the last guests at a wedding. Quite who the music was for it's hard to say, given that most of our fellow guests seemed to be middle-aged European architects. "It's not cosy. It's the opposite of cosy," my other guest Joanna grumbled, prodding at her deconstructed apple crumble.

Our bill for three came to £200, including a £32 carafe of Riesling, chosen and ordered by me, but given to James, the male guest, to taste. Not very modern, in this most modern of environments. But that summed up The Magazine experience; poised between the formality of fine-dining and the let's-wheel-the-decks-out-now grooviness of the pop-up, it's a restaurant that doesn't seem to have quite worked out what it is yet.

The Serpentine's tireless directors are right to try and fill Zaha Hadid's dream-like space with a food offer that's equally ambitious, and clearly there is something clever and interesting going on in the kitchen. But maybe the huge proportions of that glacial exoskeleton of a room were always going to be difficult to animate with heart and soul. Lange and his team may need to settle down and simplify if they don't want to end up as the restaurant equivalent of performance art; stimulating for a single experience, but you tend not to go back.

Food ***
Ambience ***
Architecture *****

Serpentine Sackler Gallery, Kensington Gardens London W2 (020-7298 7552). Around £70 per head, including wine