It's a game, dear man, a shadowy game. We're playing cat and mouse, the professor and I.
Victorian Europe, international intrigue, and daggers in the dark. How we've missed you, Holmes.
Remember what I said about hats in my Sucker Punch review? The three main female characters, all very lovely women*, all wear hats. Sim spends the last 40 minutes or so in what looks like a rumpled fedora.
Moriarty is quite chilling, and indeed Holmes match. He threatens murder and worse as easily as most people would ask the time.
The cinematography has been turned up to eleven. WB apparently went ShutUpAndTakeMyMoney.jpg to Guy Ritchie, and boy does it show, especially in one sequence I can't say any more about for fear of spoilers.
Holmes himself, as Watson observes, seems more manic. Between Watson leaving and pursuing "the biggest case of [his] career" while living on stimulants and very little sleep, it's no wonder. Everyone seems very capable, even Mary. There's an underlying sense of urgency that makes the slowdowns all the more important, more treasured.
Also, Holmes deductive sequences? He doesn't explain those anymore. We just have montages of the things he saw and we missed or thought nothing of. No explanation, the audience has to figure out themselves, drawing them into the movie. Not that this slows down the pacing. If your jaw isn't dropping, you'll be giggling.
TL:DR; If you liked the first movie, it's more of the same, but bigger and louder and better and more bromantical. Which is a word now. Every time you use it, you have to pay me a nickel.
*All with rather nice cheekbones, as it happens. The director was previously married to Madonna. I'm noticing a theme here.