The Big Picture: Jurassic Park (PG)

Director: Joe Johnston, starring: Sam Neill, Tea Leoni, William H Macy, 92 mins

The title alone should be sufficient to put you on your guard. By the time a movie franchise has "3" after its name, you can be pretty sure the game's up and that cynicism has vanquished all claims to artistic worth or integrity. Even Scream 3, for all its postmodern scoffing at the idea of sequels, couldn't save itself from being the weakest of the trilogy. Yet at least that started with Scream. What promise did Jurassic Park ever hold for the sequel cycle?

Imagine my surprise, then, to find that Jurassic Park III not only beats the first JP and its sequel The Lost World into a cocked pith helmet, but also manages to be a perfectly enjoyable monster movie in its own right. There may be a number of reasons for this. Steven Spielberg has become executive producer and ceded the director's chair to Joe Johnston, whose knack for intelligent boy's-own stuff (The Rocketeer, October Sky) and computer-generated mischief (Jumanji) proves good grounding for the thrills and spills in store. Then there is the script, by Peter Buchman and the pair of wags, Alexander Payne and Jim Taylor, who wrote the gloriously acerbic Election; there isn't quite the same astringency here, but they have at least stripped away the self-indulgence of the earlier movies. What was once ponderous is now all speed and economy: no solemn scientific preamble, no eco-sermons, just a 90-minute roller-coaster ride through a nightmare theme park, with lots of running and screaming.

Not everything is different, mind. There is still a plot that hinges on the anxiety of parent-child separation – unmistakable Spielberg – though this time the kid has the decency to disappear at the start while paragliding over the restricted territory of Isla Sorna. The reason it's restricted? Because it's home to those creatures from long ago – you know, the dinos. Not coincidentally, this is the same place of which Dr Alan Grant (Sam Neill) has vowed that "no force of heaven or earth will get me on that island" – so of course within 10 minutes he and his assistant Billy (Alessandro Nivola) are on the way there in a light aircraft, accompanying a millionaire adventurer, Paul Kirby (William H Macy) and his wife Amanda (Téa Leoni), who've promised the doc all the research money he wants if he agrees to play tour guide. Unfortunately the plane crashlands, having narrowly avoided a reptile the size of a tower block, and next thing you know the creature – a spinosaurus, since you ask – is shaking the fuselage like a tube of Pringles, trying to dislodge the human contents.

This vicious brute, with its alligator snout, is even bigger, uglier and meaner than a Tyrannosaurus rex, whose belated appearance on the scene is all that prevents Grant and friends becoming an instant spino snack. For once, you wouldn't back the T rex in a straight fight. The spinosaurus isn't the only debutant JPIII welcomes to the menagerie: that grotesquely beaked and sculpted airborne thingummy is a pteranodon, and it snatches up humans with the predatory ease of an eagle pouncing on a rabbit. Scariest of all, however, remains the velociraptor, and it still knows how to make an entrance. Having taken refuge in an old laboratory, Leoni is peering at what seems to be the pickled head of a raptor when – aaagh! – the monster crashes through the glass. The sly thing was playing stalk-and-strike.

Such guile is not news to Dr Grant, whose researches into raptor behaviour have disclosed evidence that they are not just fierce and intelligent but "socially sophisticated" – an unbidden image of the raptors sipping martinis and playing bridge came to mind at this point. Even more alarming is his discovery that they can speak to one another; the film-makers have decided not to provide subtitles to their harsh cawing, though on at least a couple of occasions the tone was reminiscent of an old girlfriend of mine, and the sense was plain: I think "Grub's up!" would cover it.

As the search for the lost child intensifies, the script draws a parallel between Leoni's maternal instincts and the fierce protectiveness of the monsters over their brood; Billy has committed the schoolboy error of stealing raptor eggs. Like us, the creatures just want to keep the family together, and a nose-to-nose confrontation with Leoni seems to prove the point.

Whereas Spielberg might have milked the theme for pathos, director Johnston prefers to make the point and then move on to the next round of terrors. He is determined not to let us settle for an instant, and in one sequence he craftily melds heartwarming reunion with horrific danger; the missing kid is guided back to his family by following the bleep of his dad's satellite phone. "How did you find me?" asks the overjoyed father. "I followed the signal on your phone," the kid replies; at which the father points out that he no longer has the phone – he gave it to that poor guy who got... And the whereabouts of the phone is suddenly made clear as they turn to gaze on the beast that swallowed it. It's a fiendish switch of tone.

Jurassic Park III may be hack work, but it's hack work carried out with precision and performed with a heart. Sam Neill's anchoring presence is always reassuring, and the smart character acting of Téa Leoni and William H Macy (the latter playing a mouse who finds his roar) is of an order you don't often find in genre work-outs. Truly, I never imagined that Parklife could be such fun.