It's been said nothing's as scary in daylight. Since fears come from the imagination, you only need to wrestle them up into the real world, and they'll turn into something you could invite home for tea. David Cronenberg's Spider (written by Patrick McGrath) skitters after that homily with a fangful of neurotoxin. The scariest things of all, it contends, our imaginations disguise by any means necessary. And when they do emerge into reality, we can look at them as long as we want. They'll only get worse.

Cronenberg makes mindfucking movies about damaged, bizarre people. That's just his thing. He's never content, though, to strip-mine a little patch of the bizarre -- he doesn't repeat himself, and so his movies are never just predictably unpredictable. The interior territory is mapless, but surely as wide as the world, and Cronenberg's been all across it.

Spider comes off as small and stale in comparison to much of this work, despite some subtly powerful performances, and an approach to visuals and narrative that's always queasily inventive. There's just not much under it all; it feels like the master idea-conjurer is dressing up a failure of imagination.

It's certainly gutsy to create a protagonist who does little but mutter incoherently, smoke, and stare at things as they go by – hardly just passive, he’s two steps away from comatose. Playing 'Spider' Clegg, a middle-aged Briton afflicted with severe schizophrenia, Ralph Fiennes mutters with nuance and stares with flair. Fascinating, inscrutable purpose winks up from his performance, but if all we saw was Clegg's external surroundings, we'd never understand a thing.

Instead, the story takes place within him. As he wanders London, its streets metamorphose into a labyrinth of childhood memories. Clegg is a literal spectator to his own derangement. Fiennes' wasted, fiftyish man lurks in corners and regards a family crisis unfolding around his ten-year-old self, trying to comprehend its shattering implications. The event may have been caused by the young Clegg’s madness – or else made schizophrenia necessary as a defense from reality’s terrors.

The young Clegg is deftly handled by Bradley Hall (who upstages his adult version with a haunted ambiguity uncommon in such a young actor), and taken individually, his scenes are consistently misleading and unsettling. They could have made a spectacular movie.

In comparison, the present doesn't pull its weight. There's a thin story about Clegg's difficulty in adapting to a halfway house for the mentally ill, and two or three interesting characters within (John Neville evokes a broken-down version of his title role in Baron Munchausen: dapper, obsequious, and utterly mad), but the situation comes to nothing at all. A failure as framework for the film's psychological delving, it feels irrelevant and incomplete, and – frustratingly - provides no insight into Clegg's past.

Insight is what we're constantly missing. The script clings to schizophrenia's realities at the expense of psychological complexity; Clegg is opaque, even robotic. Fiennes brings a breathless, eerie intensity to the character, making things compelling moment-by-moment, but he lacks the opportunity to make any moment distinct.

I’ll remember the visuals, though. Cronenberg knows how to startle (think of Crash or Naked Lunch), but Spider enthralls with subdued calm. The light’s phlegmy grey or green-toned, or else has a horrible sterile glint, like the sun’s a fluorescent bulb. Nothing’s ever solid or trustworthy – the world’s as schizophrenic as the protagonist. Negating the barrier between these two is one place Spider does excel.

Certainly the movie’s finest scene takes its power from visual innovation. It combines two recurrent images. First, spider-webs, like the freakishly intricate ones that the young Clegg’s always tying with string. Second, puzzles – in the halfway house, there’s a massive jigsaw that Clegg can no more complete than he can gather the pieces of his mind. When a huge glass door breaks in the halfway house, the attendants reassemble it to ensure there’s no more glass lying around. Clegg produces the last piece and lays it down with a click; mended, the broken glass resembles nothing but an immense spiderweb.

The movie believes it’s something like that scene: a sharp and intricate puzzle, dangerous to fit together. But it’s a more standard spiderweb. Striking in the right light, well-crafted, but insubstantial. A real complexity of ideas would justify Spider’s superficial narrative and flat characters, but there’s nothing to challenge the mind here. Your hand could go right through it.

(I did this review for a film-studies class. Recurrent Themes In Canadian Cinema. I say this as if it were relevant.)