Venom, one of the few Marvel properties still not back in the hands of Marvel Studios, has no idea what it is.

For nearly the first half of the film, Venom is a gritty thriller involving an investigative reporter, a megalomaniacal industrialist and a quartet of alien symbiotes who are quietly infecting, and then killing, pretty much everyone they come in contact with.

Then one of the symbiotes finds Eddie Brock, the reporter, who has fallen from favor after trying to take down the megalomaniac, and suddenly the movie is a screwball buddy comedy, where one of the buddies is made up of black goo and bites the heads off anyone who gets in his way.

And, out of nowhere, the symbiote known as Venom, who has been working persistently toward his goal of world domination, decides to betray his own kind and save the Earth from invasion because, well, reasons.

"On my planet I am kind of a loser, like you," he tells Eddie, by way of explaining his abrupt change of heart. And, like that, Venom is willing to kill his own kind to save a planet he has only just decided he kind of likes.

Tom Hardy is Eddie, who -- despite having a successful network news job at the start of the movie -- is kind of a scruffy and shiftless layabout. He loses his job and his fiancee -- Michelle Williams as Anne Weying, a lawyer -- after stealing confidential information from Weying's laptop in a bid to take down Carlton Drake, the industrialist, played by Riz Ahmed, who has been experimenting on the symbiotes after his private team of astronauts find them on a comet (?) and bring some back to Earth to create human-alien hybrids (?) so that people can survive in space once this planet becomes uninhabitable. Then Carlton himself gets infected and, BOOM, symbiote fight.

Other than some issues with plot and tone, however, Venom has a pretty good handle on the complex character. Set in San Francisco, the movie establishes its main characters and their motivations solidly before Eddie -- lured into Carlton's secret lab by a whistle-blowing researcher -- comes into contact with one of the symbiotes and becomes Venom.

Hardy, as Brock, is great. He's tortured, confused and a bit goofy, and the mix works ... although his reaction to biting off people's heads and, in some cases, eating them entirely does seem a little lackluster, considering that he's an active participant in the gruesome violence. Williams and Ahmed also do a great job with their roles.

Other characters include Scott Haze as Roland Treece, Carlton's head of security; Reid Scott as Dr. Dan Lewis, Anne's rebound boyfriend who becomes genuinely concerned for Eddie's welfare after an incident in a lobster tank; and Jenny Slate as Dr. Dora Skirth, the aforementioned whistle-blower. A brief, post-credits scene with Woody Harrelson as Cletus Kasady promises that the homicidal symbiote villain Carnage will be the primary antagonist in the upcoming sequel.

So, is Venom a good movie? Yes and no. It's not a perfect vehicle for the popular character, although it certainly does a far better job than Venom's infamous appearance in Spider-Man 3. A great cast help bridge the gap between some of the problems I mentioned with plot and tone. It doesn't rank among the best of Marvel's ongoing cinematic empire, nor does it hit the same self-aware and comical heights as the Deadpool series being produced over at 20th Century Fox.

But it does a pretty good job being what it is. The special effects -- Venom and the other symbiotes are pretty much all CGI, of course -- are stellar, particularly in the climactic alien-on-alien fight.

And, yes, the world can use a few comic-book flicks that aren't coming straight from Marvel and DC themselves.

Note: In the comics, Venom is a villain -- and, later, eventually anti-hero -- in the Spider-Man canon. But since Marvel has a lock on most of those properties -- Spider-Man is back in the Marvel stable after several film outings with Sony and Columbia over the years -- there only oblique references to the backstory: Brock's former job with the Daily Bugle, for instance, and a brief, short-lived cameo by JJ Jameson's astronaut son.