Part “The Fly” and part “RoboCop” (with the callous brutality of “Schindler’s List,” the jerky, cinéma vérité of “Cloverfield” and the coexistent nightmare of TV’s “Alien Nation”), a promising premise quickly turns into a stylized “Gunfight at the O.K. Corral”— meaning that the Peter Jacksonproduced, South African-made

“District 9” is little more than a rehashed mishmash of genres, films and familiar premises.

Twenty years ago, you see, a lone alien spacecraft, reminiscent of both “Independence Day” and “Battle Angel,” appears over Johannesburg and hovers without any apparent intention. When intrepid humans finally enter the craft, they find a million or so alien beings, starving and confused, apparently lost and lacking leadership.

Why did they come? Ah, good question. As is our way (and that would be the human way), our initial burst of compassion leads to forgotten curiosity, complacency and, finally, annoyance. The interplanetary visitors are eventually shunted away to a nearby slum, confined and segregated from their human hosts.

Somewhere I heard the phrase “moral intelligence” attached to “District 9”—as if by depicting the imprisonment of illegal aliens (of the real alien variety) our current and PCsavvy repulsion of apartheid or bigotry would automatically bond us to the film and perhaps make it gobs of money, too. Give the alien species a condescending name (“prawn”) and ban them from our shops and parks, and we’re supposed to shake our heads and gnash our teeth.

But without a cohesive story, without empathetic characters, it’s difficult to get riled. Then the gunfire starts—and, yes, there are some nifty splatter scenes and even some fauxsentimental human/alien bonding. But just when things begin to get interesting . . . wait, wait , why are the closing credits rolling?

If you want the real lowdown on human behavior, check out Fernando Meirelle’s “Cidade de Deus” (“City of God”) or the aforementioned “Schindler’s List.” “District 9” is pretty much a sheep in wolf’s clothing, decent eye-candy for the otherwise bored or disenfranchised but not even close to being great sci-fi. I’m not sure where the great science fiction has gone recently—not toward Hollywood nor to Johannesburg but apparently as far away as possible from theaters.

I desperately hope it returns soon to suck my brain. “Isn’t it strange,” Claire (Rachel McAdams) says to her husband, Henry (Eric Bana).

“No,” he replies. “I think it’s magical.”

Which is pretty much the pact that we, the audience, must make with “The Time Traveler’s Wife” from the getgo. Yeah, the first few scenes might seem strange and disjointed, but if you allow yourself to anticipate the magic, I dare to predict that magical things will follow.

Okay, two admissions. I loved the book, and I love the “timetripping” genre. Take me to Mars or to Altair IV and I’m happy, but whisk me back to last Thursday and I’m ecstatic.

“The Time Traveler’s Wife” takes us on a fanciful journey both backwards and forwards. Henry’s an unwitting time traveler; it’s a genetic defect that he’s powerless to control. Claire’s his stay-at-now wife, never sure of his arrivals or departures, and that makes for some interesting relationship issues.

The film isn’t a comedy. Not even remotely. It is a drama, a film vying for our genuine emotion— a story about love and our capacity to cope. One can look at time travel as a metaphor for Parkinson’s or cancer, of adaptation and the ability to love despite the odds. It’s just that time travel throws a quirky monkey-wrench of illusion, of fantasy into the machinery, spins us off to another dimension, one we’ve never been to. Hollywood’s very good at that (when Hollywood gets it right), and I do believe that with “The Time Traveler’s Wife,” Hollywood’s got it dead on.

The ultimate litmus test? If you liked “The Lake House,” then this one’s a shoo-in. If you didn’t, well, “Transformers” is still playing here and there. Me? I like the impossible notion of last Thursday potentially being my tomorrow. I like the magic.