(CNN) -- According to the "Guinness Book of World Records," Sherlock Holmes is the most popular role in the movies.
So if Robert Downey Jr. hardly seems like the iconic Sherlock (he's too short and muscular, and strains to suggest the intellectual arrogance that comes so easily to the English), he can take his place alongside such oddball castings as Buster Keaton, Charlton Heston and George C. Scott. And he's ideally suited to director Guy Ritchie's purpose, which is not to dust off your grandfather's Conan Doyle, but to juice today's kids with a quirky 19th century super sleuth.
What's fun about these movies is that the equation works both ways.
Yes, this Holmes is more likely to get physical than his predecessors, he's even a bit of a boor, but he's still a more cerebral action hero than we find in most blockbusters, and the period trappings (a seamless blend of CGI and location work) help this franchise stand out from the crowd of comic book adaptations.
Ritchie and husband-and-wife screenwriters Kieran and Michele Mulroney ("Paper Man") map out a fast-moving -- if ridiculously digressive -- Victorian adventure that crisscrosses Europe by horseless carriage, train, boat, and, in Sherlock's case, pony.
Just down the road from 221 Baker Street they're digging a tunnel for what will become the London Underground. The Industrial Age is beginning to stretch its muscles, while a series of terrorist atrocities are gnawing at the fragile understanding between the great European powers. Holmes detects something other than social unrest behind the bombings: an evil master plan leading inexorably to his nemesis, Professor Moriarty (Jared Harris).
There are big themes there, but the movie doesn't take itself remotely seriously. This is a rambunctious romp, even brazenly camp when it's poking fun at the always-intriguing Holmes-Watson relationship. Sometimes it seems like the real motivation behind Moriarty's scheme is not to plunge Europe into war so much as to prevent the doctor from consummating his marriage and reunite him with his former roommate, which is where he rightfully belongs.
Nothing if not versatile, Downey dons myriad disguises through the course of the movie (he even impersonates a bookcase), and he does a long, very funny turn in drag. Jude Law is Hardy to his Laurel, always piqued, but somehow affectionate in his aggravation. And Ritchie has the good instincts to let their byplay run the show.
They make such a splendid comic double-act, there's not much more than a look-in for the fairer sex. Sherlock's main squeeze, Rachel McAdams' Irene Adler, scarcely makes it to the opening titles. Watson's intended, Kelly Reilly, fares a little better, but her most memorable scene comes when the great detective rudely shoves her out of a moving train.
As for Noomi Rapace, the original "Girl with a Dragon Tattoo," at least she comes along for the ride as a gypsy soothsayer with anarchist tendencies, but the screenwriters' appear to forget about her existence whenever things start to get exciting.
No matter. The movie has more than its share of good gags, and if Ritchie's tic-y histrionics with the camera are starting to flag (I think we've seen the pre-rehearsed fisticuffs more than enough now, thanks), he's a dab hand in the editing suite. Playful and polished, "Game of Shadows" is at least as much fun as its predecessor.
"Who taught you to dance?" asks Sherlock, as he waltzes the good doctor through another deadly scrape. "You did," comes the inevitable reply.
They make a lovely couple.