It is daunting to revisit beloved films from one’s past, as memory makes fools of us all. Are the movies we grew up loving actually good, or do we simply have nostalgia for them? Will they resonate as clearly as we enter our fourth decade as they did at the end of our second?

It was with such trepidation that I approached “Donnie Darko,” Richard Kelly’s cult classic released in theaters 20 years ago this week. Is it just a film that appealed to a cynical teen whose puckish side found the inversion of “It’s a Wonderful Life” amusing? Or does it appeal to me still?

Though it flamed out on release — there was not much appetite for a movie featuring a plane crash in the weeks after September 11, 2001 — the film quickly found an audience in the booming DVD market, becoming a staple purchase for college-bound kids alongside pictures like “The Boondock Saints” and “Super Troopers.”

The 9/11 issue aside, one can see why “Donnie Darko” might have had trouble taking off in wide release. Starring an almost-unknown Jake Gyllenhaal as the titular teen, the film is decidedly weird. Donnie is plagued by visions of a man in a horrifying bunny suit warning of the end of the world — though one of these visions appears to save his life; an airplane engine lands right on his bed during a nighttime walkabout directed by the visions. Is this a manifestation of schizophrenia, or something more? What should we make of the bubbles that protrude from his friends’ and family’s chests and seem to guide them about, invisible to all except Donnie?

Set aside the sci-fi elements that edge up to horror, however, and the story is pretty straightforward. It’s about a kid who is vexed by bullies and resents his parents for insisting he see a psychiatrist. Donnie might be disturbed, but he’s also quite smart, seeing through the new-age twaddle he’s peddled that all actions are driven either by hate or by love. The movie is quintessential alienation art for adolescents, the sort designed to comfort intelligent kids by reminding them they’re not as alone as they sometimes feel themselves to be; no wonder it became a dorm-room classic.

And yet, what jumped out at me 20 years later was the fact that the adults in the film weren’t simple stereotypes of oppressive adults. Donnie’s teachers are largely supportive of the strange boy in their care, within the limits of what their roles allow. The excitement that gives way to reticence as Professor Monnitoff (Noah Wyle) discusses theoretical physics with Donnie before realizing that they’re drifting into religious talk — a discussion that could get him dismissed — is heartbreaking. So is the firing of Karen Pomeroy (Drew Barrymore, who was one of the key figures in getting the film made) for assigning a short story about vandalism that inspires a copycat action.

Even Jim Cunningham (Patrick Swayze, in one of his last great roles) feels like a real, if evil, person. He’s the self-help guru who pioneered that love-hate dichotomy, and you can see why his charismatic shtick would appeal to adults and kids alike. It’s also easy to understand how the townspeople could be beguiled into accepting this pervert who, by film’s end, is revealed to possess child pornography.

What resonates most, though, now that I have two kids of my own, is that Donnie’s mom and dad (Mary McDonnell and Holmes Osborne) are genuinely loving, if somewhat overwhelmed by the troubled young man Donnie seems to be turning into. They’re not “cool” parents; they’re not offering their kids booze or trying to be best buds with them. They just feel, well, real: busy with work, supportive when they can be, trying to connect.

This is largely thanks to Osborne and McDonnell’s performances; they are wonderful in the roles they’ve been given, stifling laughs when their kids say something outré and holding back tears when they come up against the limits of what they can do to help Donnie. We can see how deeply they care for all their children, even if they don’t know exactly what to do with them.

“Donnie Darko” has aged into adulthood nicely, even if its protagonist never got the chance. Yes, its relevance is most keen for any weirdo who has suffered the estranging effects of school and teenage social life. But viewers of all ages and stations can find something to identify with, an anchor to keep them in place even as the film’s odder ideas still swirl about 20 years on.