Kermit the Frog said that it’s not easy being green, and it apparently wasn’t easy for DC Comics to bring their “Emerald Warrior” to the screen, either. “Green Lantern” is visually quite interesting, making mostly good use of effects that have comic-book splashiness to them.

But the movie suffers from kind of bipolar disorder. On the one hand, much of it has the seriousness of the old books and the recent reboot. But the makers were apparently afraid that a perfectly straight adaptation might suffer the fate of “Superman Returns,” which treated the source material with a degree of sincerity that modern audience found impossible to swallow and presented action sequences that were more balletic than viscerally exciting.

So they’ve combined that element with a jokier one that turns the hero into a callow hipster more in tune with today’s juvenile sensibilities. He may be called Hal Jordan and be a great test pilot, but in terms of personality the hero is a great deal closer to that other Lantern, Kyle Raynor. (Fans will know what I mean.) And to play him the makers have a cast a guy who’s virtually the embodiment of frat-boy smugness, Ryan Reynolds, and given him plenty of big, boisterous action to engage in. It’s a mixture that frankly doesn’t gel; the combination of earnestness and smart-ass wisecracks proves unstable.

The plot is a mixture of the old and the new. Hotshot pilot Jordan is summoned by the power ring of dying GL Abin Sur (Temuera Morrison), who’s crashed on earth, to become his successor. Before long Jordan is learning to use the ring and its accompanying lantern to perform heroic feats as the costumed guy by using his force of will to summon up green projections of things he imagines, from racetracks to guns. He’s helped in this by a training session on the planet Oa, homeworld of the Guardians who established the Green Lantern Corps, under the tutelage of courteous Tomar-Re (voiced by Geoffrey Rush) and muscle-man Kilowog (Michael Clarke Duncan), though Lantern leader Sinestro (Mark Strong) doubts that a mere earthling can ever make the grade.

But Hal has psychological problems stemming from the death of his dad, also a pilot, in a fiery crash shown in the inevitable flashback. And it’s not long before his mettle is tested. The planet-destroying Parallax, a blob of energy voiced by Clancy Brown), which was responsible for Abin Sur’s death and feeds on the fear that is the opposite of the Lanterns’ will, threatens earth, and Jordan must battle it to save his world. Also involved in the struggle is Hector Hammond (Peter Sarsgaard), a strange scientist—and son of a US senator (Tim Robbins)—who’s always been Jordan’s geeky revival for the affections of Carol Ferris (Blake Lively), daughter of the owner of the aircraft firm where Hal works. Hammond is somehow taken over by Parallax and, in mutated form, prepares the way for his master’s arrival by taking on GL.

If all this sounds confusing in the reading, it certainly will be so to uninitiated viewers, requiring reams of introductory exposition intoned by Rush over a long prologue and periodic bursts of explanation thereafter. In the end, though, it all comes down to a simple message—that the key to success isn’t being without fear, but laying oneself on the line to overcome it—though it’s expressed in terms of a final titanic battle between the embodiment of fear and the power of will.

Fans of the comics will probably appreciate the fidelity to the basic contours of the DC mythology (and to the GL costume, as well as the look of the supporting extraterrestrial figures), which draws on both the Silver Age books and the more recent ones. They might be more annoyed with the reworking of Hammond and the introduction of his father, though even here there are some connections with the books. How they react to the alteration of Jordan’s character, and to Reynolds’ performance, is more uncertain. Certainly the star looks the part in his GL outfit, but even in an origin story his boyishness gets grating pretty quickly. Among the rest of the cast Mark Strong is a stern Sinestro (a future villain, as a final credits shot suggests, should a sequel emerge), and Sarsgaard is a hammy hoot as the oddball Hammond. But everyone else is decidedly bland, especially Lively, whose lack of chemistry with Reynolds reduces the romantic subplot to negligibility.

On the other hand, those coming to the movie without a grounding in the comics will probably be at sea more often than not, and perhaps find a villain rather similar to the planet-eating Galactus of the second “Fantastic Four” feature a mite repetitive. (The CGI of Parallax, moreover, isn’t all that great.) Still, they should be taken by the effects, which aren’t at all realistic but have a bright comic sheen that’s pretty impressive. Unfortunately, the images are dulled by the 3D process, which darkens them to such an extent that some detail is lost. As usual, one might be better served by the 2D version. But no change of visual format will improve James Newton Howard’s generically souped-up score.

So the verdict on “Green Lantern” is that it’s an average superhero movie that’s fails to establish a coherent identity that might transform it into a long-running franchise. It’s better than “Green Hornet” (or “Green Berets” or “Green Card,” for that matter), but once you get beyond those color-based comparisons, it quickly pales.