This isn't the movie the critics--and, apparently, its makers--took it for. In interviews the actors and the director talked about it as if it were a straight mystery, but what it turns out to be is a Victorian pastiche, in the mode of The Assassination Bureau or The League of Gentlemen, with a farcical Holmes and Watson at its center. I personally like pastiches, but this one I didn't find very enjoyable, well appointed though it is; the violence is too nasty and most of the cast unlikable. A couple of scenes work because the dominant actors, Geraldine James and Edward Fox respectively, know how to play them; but then each disappears and we're left with the glumly miscast principals, among them the estimable Mark Strong, who might have made an interesting Holmes but is stranded playing a stock villain. In addition, the story is boring: Holmes' deductions are superfluous, none of the characters has a stake in the outcome, nothing that can happen will make any difference. The whole thing just floats away.
Review of Sherlock Holmes
