FORGET Schwarzenegger and Stallone. There's one movie that's going to muscle the rest off the block this summer. Like one of the runaway dinosaurs in Michael Crichton's tale of a theme park gone wrong, Jurassic Park is stomping all over the box office, across headlines and into the public consciousness. Last weekend, it earned an estimated US$50 million (HK$387 million) in the US - the biggest opening in film history. It also boasted the biggest single box-office day return (US$18 million). By conservative film industry estimates, it will make US$200 million at the box office in North America alone before it conquers the rest of the world (although Hongkong audiences have to wait until late next month). The studio will then set its sights on the estimated US$500 million Batman (the original) made from film-related merchandise - which was double what the film itself earned. More than 100 companies are clinging to the Jurassic bandwagon, hawking more than 1,000 products worldwide. Books, dolls, posters, clothes, shoes, lunch boxes, toys, comics . . . you name it, they'll sell it. And kids will buy it. They may be scared by Jurassic Park, they will be entertained and they are bound to want a bit of the movie's magic. And it was the promise of that magic which took The Guide to Los Angeles in the frenzied week before its opening todiscover what had happened to the Crichton best seller. The answer? Simple. Steven Spielberg had happened to it. ''We are looking at something beyond a very skilfully constructed dinosaur film,'' Crichton said. ''Jurassic Park is a true movie milestone,'' wrote one critic. ''Wow,'' said everyone after the press screening of the film. Crichton and David Koepp's screenplay for Jurassic Park sees paleontologist Sam Neill, paleobotanist Laura Dern and mathematician Jeff Goldblum invited to a remote island off Costa Rica where super-rich scientist/visionary Sir Richard Attenborough has created a theme park with a difference. Thanks to a DNA cloning technique, he has (re)created several species of dinosaur and endeavoured to let them roam around a massive game park. But, with two precocious kids in tow, the park's first visitors soon discover that when things go wrong in Jurassic Park, they do so in a big, big way. Jurassic Park is a hugely entertaining film, one filled with how-did-they-do-that moments, chills reminiscent of Jaws and moments of wonder like those in E.T. or Close Encounters. The casting seems to have been deliberately low-key. With respect to Dern, Neill and Goldblum, there are no A-list names getting in the way of the real stars: the dinosaurs. From the terrifying Tyrannosaurus Rex to the sinister velociraptors and a vast, benign brachiosaurus, the dinosaurs look, well, real. That is, if we knew what they actually looked like. Thanks to technological breakthroughs in mechanical and computer-generated effects, a star-studded team (whose credits include Star Wars and Terminator 2 ) created a new reality. ''What we did is nothing less than a paleontological reconstruction,'' explained Academy Award-winning animator Phil Tippett. ''So even though it is a fantastic premise, Steven Spielberg's direction from the beginning was to be as paleontologically accurate as we could be. He didn't want anyone coming back and saying 'that's a fake, that could never happen'.'' The effects people also admit they would not have been there were it not for one man: Spielberg. No one else in the world could have directed Jurassic Park. He is the most accomplished director of special effects in history, with a talent for eliciting strong performances from actors playing alongside matte screens or inanimate objects, and with the knack of not letting effects get out of hand. ''The dinosaur effects of this movie are going to get an enormous amount of acclaim,'' said F/X genius Stan Winston. ''But, in fact, the movie exists and the dinosaur effects are as good as they are because of Steven Spielberg.'' Neill said: ''I love the way he works. He plans meticulously. But his metabolism is so sped up that he's always thinking three squares ahead of himself. ''I also think he's much underestimated as a director of actors.'' And Dern said Spielberg was totally devoted to his vision. ''Steven wants to create make-believe and make it come true for himself and for all the little kids. And those are the movies he will make.''