When that movie based on “Super Mario Brothers” hit the theaters years ago, many flinched at the thought of a movie genre based on video games. “Mortal Kombat” bore out our collective fear.

Now we’ve been presented with “Pirates of the Caribbean,” complete with a conspicuous “Haunted Mansion” preview before the movie even begins. Ugh. A genre based on theme-park rides? How long before a movie based on that rollercoaster based on the Batman movies?

But then you think, “Hey, Johnny Depp. When has he let me down?” And you ignore his few god-awful movies and bite. He is the Brando of his day. We will see any movie featuring either star of “Don Juan de Marco,” convinced that, though the film may suck, there will be at least one intriguing performance.

To belabor the analogy, “Pirates” is to Depp as “The Island of Doctor Moreau” is to Brando, except that “Pirates” is enjoyable beyond Depp’s performance. But it is his nearly ridiculous, dashing, drunken, eye-liner-masked fop that outshines even the most majestic colonial seascape.

As Brando’s bizarre Moreau defined a new twist on the mad-scientist type, Depp’s Captain Jack Sparrow is a new, weirder type of pirate. Like Brando, Depp pushes his character just to the edge of believability. It is that extremism that makes the character and the movie both amusing and compelling.

“Pirates” has a Disney-esque quality, but with a subtext of weirdness, and none of that insipid singing that haunts Disney animated movies. “Pirates” isn’t quite the Disney Nasty we’ve always wanted, but it offers a darker side to Disneyworld’s coolest ride.

Orlando Bloom, still appealing despite shorter, darker hair than in “Lord of the Rings” (and a rather amateurish mustache), provides the human element to this mythic tale. He is the live-action version of a Disney animated-film hero but, again, without the damn singing.

He is partnered with the flamboyant Depp in an attempt to thwart a bunch of pirates — led with admirable garishness by Geoffrey Rush (“Quills”) — from sacrificing his would-be girlfriend (Keira Knightly, “Bend it Like Beckham”). The sacrifice will, in theory, end the pirates’ undead curse. And, yes, the pirates’ ship is called “The Black Pearl.”

The film is rather long, and not completely convincing. But, if you’re in the spirit of it all, you ignore this. Nearly as much as Depp, it is Geoffrey Rush who gets us into the spirit. He is slimy and wicked; occasionally venomous, but also earnest.

So, despite its length and despite several contrived plot twists that add to its length and despite touches of absurdity that keep it from any hope of being completely convincing or dramatic and despite … well, for all its faults, real or perceived, it’s damned entertaining.

The scenery is beautifully photographed, and director Gore Verbinski (“The Ring”) immerses us in a vivid environment. The look of the film speaks honestly of the era — both dirty and gilded — while still finding room for clever, semi-subtle references to the actual Disneyland/Disneyworld ride.

Movies that simply entertain without insulting the viewer’s intelligence are a rare breed. “Pirates of the Caribbean” is classic popcorn fare, and it features a light-but-brilliant performance by Johnny Depp, the Gen-X Marlon Brando. So why haven’t you seen it yet?

Grade: A