It's a pity '60s nostalgia hasn't really caught on, because if it had, "Birdy" could be a big hit -- it's what used to be called a "head movie" (as in "acid head"), with dazzling visuals, jumbled editing and a starved, disconnected story line.

Based on the novel by the pseudonymous William Wharton, "Birdy" follows two veterans in a VA mental hospital (the war, in the movie, has been updated to Vietnam). Al (Nicolas Cage) hobbles around with an elaborate bandage hiding half his face (the better part of his jaw was blown off by mortar fire); Birdy (Matthew Modine), traumatized by a month spent missing in action, crawls around on his haunches, refusing to talk -- he thinks he's a bird. Al's been summoned by the resident Army psychiatrist to try to bring Birdy back to reality.

"Birdy" moves back and forth between Al's point of view and Birdy's; and it regularly flashes back to Al and Birdy's boyhood together in the slums of Philadelphia. These scenes roll with calypso music that, for Philly, is utterly incongruous, and yet somehow utterly appropriate. In the current atmosphere of paeans to some airbrushed adolescence, there's something daring about how flat, and even horrible, these flashbacks are. There's nothing mythic about "Birdy's" prom -- it's just a prom -- and when Birdy's date drops her bodice for him, he distastefully hefts a breast like a rotten cantaloupe (he prefers canaries). It's the most Swiftian moment in recent movies.

But then it's back to the loony bin. Some of director Alan Parker's compositions here are striking, expressionistic shots of dark shapes silhouetted against the blue light streaming through the asylum window. Then again, they're all the same -- after two hours, you're bored by them. The camera is static ("Birdy's" visual achievements have less to do with film than with still photography), framed by the walls of Birdy's cell, which inevitably leads Cage to Method-school acting excesses -- there's something about a bare, unpopulated room that brings out the audition in people. Cage struggles with a character that is no more than a foil to Birdy; in making the book cinematic (Birdy's character in the novel is all interior monologues), screen writers Sandy Kroopf and Jack Behr have thrown the emphasis to Al, but there's not much there -- he's mostly just a brute.

Modine, who defines charm for a generation of young actors, is more restrained; you can imagine what Timothy Hutton, who layers birdlike tics onto all his characters, would do if called upon to play a human canary. But in the asylum, there's not much for Modine to do but look fey in a fetal position. Turned loose in the flashbacks, he blossoms. Modine's face is all friendly triangles -- he's a human kaleidoscope. His charm is so light, you actually believe he can fly.

Birdy is obviously deeply disturbed, but in the movie his sexual revulsion, his avoidance of reality, are endorsed as a sane reaction to an insane society, to a life that is nasty, soot-filled and violent. "Birdy" belongs in the "who's really crazy?" genre that began with "King of Hearts" and "One Flew Over the Cuckoo's Nest" (for Big Nurse, substitute Big Shrink, John Harkins' obesely sinister Army psychiatrist). Such movies make romantic figures out of people who really need help; when we see the panhandling schizophrenic on the corner, we call him "king of hearts" and waltz by -- we become avoiders, too.