Hugh Jackman stars as the clawed hero in “X-Men Origins: Wolverine.”

The second coolest thing about the Wolverine of the X-Men movies — after Hugh Jackman’s epic sideburns — was his mystery. So naturally that’s what Marvel set out to delete with “X-Men Origins: Wolverine.”

“‘Wolverine” may be a perfectly adequate superhero comic-book movie, all explosions, chases, gunfights, sword fights and blood feuds. There’s even a little humor in it. But that irritable loner who shows up on a snowy road without a memory, with a past we can only guess at, in “X-Men”? That dude is explained away as we get 150 years of history in this movie about the mutant’s early life, his first killing, the reasons Sabretooth becomes his nemesis.

In a brisk opening, director Gavin Hood (“Tsotsi”) trots out the sickly boy James who learns his secret from his half-brother, Victor. They take their “gifts” to the battlefields of the Civil War, World War I, World War II and Vietnam. That’s where Victor (Liev Schreiber, bad-eyed and bloody) finally snaps. A village massacre brings the brothers to the attention of Stryker, played in this prequel by Danny Huston.

The brothers join an elite team of mutant killers (Ryan Reynolds, Will i. Am, Dominic Monaghan and Daniel Henney among them) and run up the body count until James has had enough. The brother with the conscience disappears, takes on a new life and a new girlfriend (Lynn Collins) until the old life sucks him back in.

But Logan, as he is now called, has the worst case of night terrors ever. And when he wakes up, screaming at the sky (he does this a lot), Kayla the lady love has to say, “Looks like we’re going to need new sheets again, babe.”

Wolverine is about Logan getting that new animal moniker, about the Weapon X program and the beginning of the military program to hunt and capture mutants.

Mainly, however, it’s about how cool Jackman looks with his new metal claws, how buff he is with his shirt off (and with his shorts off, in a couple of scenes). The chases are exciting in a conventional motorcycle vs. helicopter sort of way. The repetitive brawls always involve Wolverine and somebody else, often Sabretooth, bellowing and running at each other.

And the finale? There are two different endings, Fox tells us, damage control from the fact that the movie was leaked onto the Internet a month ago.

Often when filmmakers who have shown a talent for character, story and suspense are co-opted to make a Hollywood comic-book film, the comic book devours the director. That’s pretty much the case here with the South African Hood, who manages some grace notes but still made a movie that’s short on heart and heavy-handed, much like the Ang Lee-directed “Hulk” of a few years back. The set pieces, especially toward the end, are more amusing than awe inspiring.

But Jackman is still cool in the role, and Schreiber makes a worthy (if bizarrely sadistic) foe. Too bad Marvel pummeled the mystery out of them both.