Sequels invite second-guessing. You think you know what to expect, but then start hoping you'll get something more, something unexpected. The surprises can make it worthwhile.

Before you watch Terminator, you expect you will see Arnie striding back from the future through a blaze of mangled metal, fiery explosions and showers of lead. There will be lots of destruction, effects that meld the worlds of man and machine and riffs on the sparse dialogue of the earlier films like Ah-nold's deadpan one-liners "I'll be back" or "Hasta la vista, baby". These are ingredients that worked for the first two movies and, yes, they're back.

The storyline is familiar - think T2, but with a sexy, leather-clad blonde (Kristanna Loken) as the bad guy sent back to rewrite history by eliminating the future saviour of mankind, John Connor (Nick Stahl).

This new terminator, the T-X, is the most advanced killing machine yet. That's what we are told, although the main difference between her and the villain of T2 appears to be breasts and a few new weapons up her sleeve. Like the T2 terminator, she is virtually indestructible, can assume other peoples' shapes and voices, and tap into computer networks using a probe that comes out of her finger.

Connor, just a kid in T2, is now grown into a young man living an itinerant and anonymous lifestyle. Arnie is the good guy terminator, who is sent (again) to protect Connor on the eve of the machines' takeover of the world. There is also a girl now - a veternarian called Kate Brewster (Claire Danes), who Connor inauspiciously meets after being caught breaking into her surgery for painkillers.

The movie can be described as one long chase as the trio play cat and mouse with T-X, leaving a trail of destroyed neighbourhoods and vehicles behind them. Our human heroes live charmed lives and have that irritating habit of stopping for meaningful talk as murderous machines bear down on them. The pyrotechnics and special effects are impressive, but you really have to switch off a part of your brain at times to get into the story. The longer it goes on, the less believable it gets.

It helps that this is a funnier movie than the previous versions. Arnie, for whom this role was godsent, gets most of the good lines, delivered with monotone aplomb. There are some amusing exchanges with Connor's reluctant hero as the cyborg tries to lick him into shape.

As a physical presence the big man is impressive. He appears to have a little extra flesh around the hips, but 55-year-old Arnie is looking physically in good enough shape for a man of 20 years his younger.

Loken looks great too, but does almost too good a job of being the beautiful robot, her totally expressionless face giving nothing away.

As a whole T3 has just about got enough fresh input to keep you gripped, and by the end appears set up for an interesting new tack in T4.