How others will see it. This acclaimed film requires patience, and a tolerance for Cage's angst-filled performance. My feeling is that most people who see the movie will be slightly disappointed in it. If they see it through, they may feel something minor has been accomplished. But, certainly, minor is the adjective that best describes this acceptable filmdom entry.
How I felt about it. Why does Cage hang around Modine, when Modine is such a kook? Especially when the alternative is feeling up girls, something that Cage's character seems adept at. Modine's motivation is more understandable. He's a nutcase, and only gets worse as the flashbacks progress.
Most who are interested in birds study their species, songs, behaviour, or migration. But Modine is interested in their spirit. He wants to know what they feel, because he wants to be a bird himself, proof that the grass really is greener on the other side of the fence.
So, why does Cage hang out with him? He's (hopefully) not attracted to him, and he doesn't approve of or admire him. If he's there to help him, he's not much use, either. Modine nearly kills himself twice and gets arrested on another occasion, with Cage around.
If the motivation of the film's true lead is in question, another problem is Modine's mental illness. He makes no progress until the final few minutes of the movie. Why does he get better? Because Cage is about to leave him? Or because the allotted two hours have elapsed? And what's with all the naked shots of Modine? Does he think he'll grow feathers if he takes his clothes off?
If the characters and story don't hold up under evaluation, there are individual scenes that work. Most of these are flashbacks. Cage and Modine try to start a junk car. Cage sits in a hospital room wearing a suit of pigeon feathers (Wouldn't he have taken it off by then? Oh, it wouldn't be funny.)
Birdy ends abruptly, with a joke that shows Modine is recovered. Which is, after all, what the audience presumably wants. However, I would still like to know how they get down from the lower roof.