“Sherlock Holmes: A Game of Shadows” begins with a bang. Literally. A bomb goes off–one that Sherlock, played by the lovably roguish Robert Downey Jr., artfully diverts from blowing up a room of auctioneers.

He’s at it again–that is, always one step ahead of everyone else. Guy Ritchie’s Sherlock Holmes is not a dapper gentleman who slowly draws on his pipe and muses about things like anagrams and red herrings, but a crime-solving tour de force who maneuvers his way through a fight as effortlessly as he puts clues together. This is what taking a beloved classic and assimilating it into the “Transformers” and “Thor” mold looks like. Yet as exhausting as the pace of action is, “Holmes” is blessed with a rare wit and gameness that lends its energy a devilishly entertaining edge. I can’t help but like it.

Consider a scene (minor spoiler alert) on a moving train when Downey appears disguised as a woman to his crime-solving partner, Watson (Jude Law). A gunfight breaks out; Holmes breaks out his fists and sheds the dress–but he’s still wearing unsightly amounts of purple eye shadow and smeared red lipstick. Downey, an atypical action star if there ever was one, brings to the role a delightful slapstick that harkens back to entertainers of yore: Tony Curtis, Jack Lemmon, even Charlie Chaplin. A light bulb must’ve gone off somewhere in Hollywood after “Iron Man.” Imagine, movie people said, a classic entertainer in the shoes of an action star. What a brilliant idea.

This is a sequel better than the original. The first one had a good plot going for it (this does too, but it’s not as tight), but the sequel’s writers smartly capitalized on Holmes’ comic eccentricity and the endearingly love-hate relationship between him and Watson. The result is an action film that does the rare thing: not take itself too seriously. Just imagine putting into the driver’s seat Genie from “Aladdin” with a dash of Daniel Craig’s James Bond.

Downey’s role, in all ways, is to entertain us. With the rapid pace with which he puts clues together, the audience is hardly in a position to follow the leaps of his mind, much less solve the crimes in unison. His ingenious intellect, much like his unhinged character, is there to dazzle and surprise us. He’s always a step ahead of everyone–the audience included. It’s often frustrating to follow in his footsteps, but the dots, when they do belatedly connect in our minds, are still beguiling, especially in the well-engineered last act.

I went in expecting a mediocre yet entertaining film. Entertaining it is, but mediocre is an ill-fitting word. By no means does this movie aspire to great philosophical or artful heights; it wants to entertain you. Robert Downey Jr. wants to entertain you. Then you remember: that’s the point of movies, right? It’s the giddy thrill of thinking, “How is he going to get out of this one?” and seeing him do it, in drag.