Originally appearing as self-contained backup segments within episodes of Rocky & Bullwinkle cartoons, "Dudley Do-Right" and its characters have their roots in the serialized melodramas of early silent films. The cartoons are steeped in such iconography as the mustache-twirling villain tying the damsel to the railroad tracks (or a sawmill, etc.), the jaunty piano accompaniment, and the irising camera and old-timey title cards that introduce each character. Dudley is a spoof of the brave and pure hero: a well-meaning and idealistic buffoon, who somehow (often in spite of himself) brings the bad guys to justice.
Brendan Fraser plays Dudley as a slapstick dimwit who is as much a victim of his environment (for example, stepping on loose floor boards in his cabin) as he is of his own naïveté. He's a rather bland hero, rigidly devoted to his sense of right and wrong and hopelessly idealistic (not so much a ridiculous caricature as his cartoon counterpart). This builds a sense of sympathy for the poor guy, which was never really part of the cartoon iteration. Likewise, Nell (Sarah Jessica Parker) is fleshed out as a comically well-educated Yale and Harvard graduate (and former U.S. Ambassador to Guam), and not just a fickle frontier maiden who toys with Dudley's heart. Alfred Molina seems to have fun with his role as the dastardly Snidely Whiplash, playing it as cartoony as he can, and it works. (The character of Horse, the horse, doesn't add much and is largely absent from the film.)
The action is propelled by the wonderful, pseudo-serious narration (by Corey Burton, in the style of Paul Frees), which takes a page right from the original cartoons. But the film makes the odd choice of setting the action in the modern day (since the cartoon from the 1960s was very specifically spoofing old-timey silent movies and a late-19th-Century setting). It's just a little odd to see Dudley standing next to a modern SUV, or to have the mustachioed Snidely watching cable news. The mix of antiquated iconography and contemporary trappings is bizarre, but I suppose that's part of the film's charm. (At least we don't get a completely modernized take on the characters.)
The plot has the sinister Snidely Whiplash incite a false gold rush on his own Canadian land, bringing waves of Americans (and their wallets) over the border. Dudley faces a crisis of conscience when it's pointed out that Snidely's "wrong-doing" is actually good for the Canadian economy, and that sometimes in order to stop the "bad guy", a "good guy" has to be a little bad. (The scenes where Dudley is a "dangerous", motorcycle-riding, vigilante "bad boy" offer an interesting role-reversal with his nemesis Snidely, but stretch the character a little too far from his fumbling Mountie image.)
Despite the criticisms, DUDLEY DO-RIGHT is fun because it embraces its cartoon roots. The film is very stylized, from the portrayals of the characters to the voice-over narration to the occasional fourth wall breaks to the veins of absurdity that run through the whole thing (Snidely's merchandising empire, the faux-Native American theatrical performances, Eric Idle's prospector bum-turned-wise mentor). Although the story was transported to the modern world, the filmmakers didn't tamper too much with the spirit of the source material. The narration is on-point, Snidely's goons have some funny lines, and Molina's colorful portrayal of the villain (with his alternate outfits for playing mini-golf and leading a battalion to war) makes the film worthwhile.
When I saw the movie it was preceded by an animated "Fractured Fairy Tales" short, THE PHOX, THE BOX, & THE LOX (1999), which was a pleasant surprise and a pitch-perfect recreation of the old cartoons from Rocky & Bullwinkle (down to the vocal sound-alikes for Edward Everett Horton and Daws Butler, and the actual participation of June Foray).