CGI comes of age in Sky Captain And The World Of Tomorrow, a visually ravishing science-fiction spectacular set in a wholly synthetic digitised universe. Seamlessly integrating actors filmed on blue-screen with more than 2000 effects shots, director Kerry Conran constructs a stunning retro-reality where anything goes; and frequently does. Alas, the finest technology money can buy can't disguise basic flaws in plotting and structure, and flatly written, blandly heroic protagonists.

At first glance this shouldn't pose a problem: after all, the Saturday morning serials, monster pictures and WWII adventures Conran references were hardly renowned for their depth of characterisation or finely tuned narratives. But having constructed such a flamboyantly artificial environment just a few steps removed from a computer game, Sky Captain desperately needs a human element to anchor its stylised flights of fancy.

"THE STORY SOON GOES OFF THE RAILS"

What it has instead is Jude Law, shamelessly channelling Errol Flynn as the daredevil pilot trying to rescue New York from the huge robots that are plundering its resources. The scenes of metal behemoths stomping Manhattan underfoot and bird-like bombers swooping through its concrete canyons comprise the movie's most accomplished and exciting set-pieces. However, once Law and his reporter girlfriend Gwyneth Paltrow leave the metropolis for icy Nepal, an airborne airstrip and a Lost World-style island, the story soon goes off the rails.

Law and a Stella McCartney-garbed Paltrow, struggle gamely to fabricate a bickering screwball relationship, but any attempt to flesh out their archetypal roles is stumped by Conran's ceaseless quest for louder, flashier pyrotechnics. Giovanni Ribisi and an eye-patched Angelina Jolie fare better in supporting parts; popping up now and then to offer crucial exposition before retiring gracefully to the wings. Theirs is probably the best policy in a movie where lavish comicbook fantasy crushes all before it like one of Conran's iron giants.