C

The “whys” stack up immediately in encountering “The Incredible Hulk.” Why would Marvel and Universal think it a good idea to reboot Big Green after the financial disappointment of Ang Lee’s 2003 effort at turning the comic book variant of Dr. Jekyll and Mr. Hyde into a movie blockbuster? Why would Edward Norton, an actor of extraordinary gifts, choose to play Bruce Banner, a part that would hardly tax his talent (and that the first screen Banner, Eric Bana, reportedly declined to reprise)? Why haven’t the effects improved much in the intervening five years—Banner’s alter-ego still looks like a giant claymation construct inserted into live-action footage—Gumby on steroids, as it were—though this time around the color is more muted and the surroundings are deliberately kept dark to inhibit a clear view? And why was Louis Leterrier, whose only previous claim to fame was “Transporter 2,” hired to replace Lee?

The first and last of these questions can, at least, be easily answered. What Marvel wanted wasn’t the sort of slow, intense treatment the schizoid character got the first time around—quite successfully, in one man’s minority opinion—but instead a slam-bang, action-filled testosterone engine. That’s led to a spat between the comic company and Norton, who fought unsuccessfully for a longer, more somber cut and, when he didn’t get it, opted out of doing press interviews for the picture. (For what it’s worth, Leterrier apparently agreed with him, at least to a point.)

The result is that while this new “Hulk” is leaner (except in the animation of the big guy, who looks to have put on substantial weight over the past half-decade) and goes by faster, it’s a considerable step down from Lee’s more imaginative treatment, a very conventional comic-book movie, and not an especially impressive one at that. Basically it’s a chase-and-fight picture, which leaves the Hulk’s origin for brief flashbacks and verbal exposition and opens with Banner long on the run from the weapons-obsessed General Thaddeus “Thunderbolt” Ross (William Hurt) and settled down in the endless slums of Rio, where he’s frantically researching a cure for his condition while working for a pittance in a soft-drink bottling plant. (An establishing helicopter shot of the city goes on so long that you expect the movie to turn into “City of God 2.”)

But the general tracks Bruce down and sends in an elite force, headed by new recruit Emil Blonsky (Tim Roth) to capture him. Things don’t go as expected, of course—the Hulk reemerges when Banner’s attacked and his anger set off, and he escapes—and the scientist makes his way back to the university where the Girl He Left Behind, none other than the general’s daughter Betty (Liv Tyler), still pines for him while working in the lab. She helps Banner connect with the one researcher willing to help him, the loopy Dr. Sterns (Tim Blake Nelson), even after she witnesses what he becomes after his transformation during another botched attempt to capture him, this time with a Blonsky who’s been enhanced with the same technology that created Hulk himself, though not to the same degree. (A post-fight lovey-dovey scene shows that she’s the beauty who can tame the beast.)

But the general’s never far behind, and manages to capture Banner, much to Betty’s distress. Unfortunately for her father, the uncontrollable Blonsky, anxious to wield the same power as the Hulk, forces Sterns to use the full process on him, turning him into Abomination, one of the green guy’s old comic-book foes. That sets up a big final confrontation between the two in the streets of Harlem, which wind up far worse for wear.

It’s a pretty long fistfight, but not a terribly engaging one, because the effects are frankly second-rate, with combatants that look like a couple of globs of super-putty banging away at each other in the dark. It’s almost enough to make you appreciate the brevity of the battle in the last reel of “Iron Man.”

Of course, apart from the three big action sequences (in Rio, on the college campus, and then in the culminating battle), it’s Banner, not the Hulk, who’s on display for the most part, and sadly Norton doesn’t do much with the role. He’s an extraordinarily talented fellow, but it seems that when he takes on more ordinary leading-man parts (as in 2002’s “Red Dragon” and now here), he’s at a loss. He looks like the weak, slightly nerdy scientist stuck with a condition he’s desperate to rid himself of, but never gives the character any depth (as Bana did—perhaps to excess), and the sloppily soap-opera nature of his scenes with the mopey Tyler shows how much better Bryan Singer handled such reunion stuff in “Superman Returns.”

Then there are Roth and Hurt, both of whom exude a leering intensity so over-the-top as to become instant camp. Hurt, of course, used a similar technique to perfection in “A History of Violence,” but there it was part of David Cronenberg’s visionary combination of blood and satire. Here one wonders whether Leterrier even noticed the actor was sending things up. Nelson is the intentional comic relief, and he bumbles around in broad, obvious fashion.

That will probably amuse the target audience of fan-boys, who will probably find the movie an adequate if unexceptional screen adaptation of the comic, falling somewhere between the heights of the first two “Spider-Man” flicks (and, for some, “Iron Man”) and the dreary disappointment of “Daredevil.” Devotees will also be taken with the numerous in-jokes and cameos, from the inevitable presence of Stan Lee to an appearance by Lou Ferrigno and even, via an old clip, one by the late Bill Bixby (though “My Favorite Martian” would have been a better choice than “The Courtship of Eddie’s Father”).

And fans will be thrilled by the coda, which links this movie with Marvel’s other summer superhero extravaganza by bringing Robert Downey, Jr., briefly into the mix as Tony Stark. But in actuality it’s totally unnecessary, and may even be harmful in the long run by inviting invidious comparisons. Because this “Hulk” isn’t incredible; it’s just mediocre.