There are some power-hungry, murderous villains on the loose in London, and the city itself is presented as a fairly brutal, gritty environment. But the film also celebrates Holmes' eccentric genius and his close friendship with Watson. Though he's a cantankerous soul, Holmes clearly values his friend and even tries to save a former paramour despite the fact that she once double-crossed him.
Frequent violence, including gunplay, bloody fistfights (some in slow-motion, detailing each painful blow in wince-inducing fashion), and a few big explosions. Guns, knives, a rudimentary Taser, and poison are used in various face-offs; corpses are displayed (in dirt with maggots visible, singed to a crisp after being engulfed in flames, dead in bathtub water). Men are shown hanging from a noose; a woman nearly stabs herself. Animal carcasses are shown hanging and sawed in half; a frog is shown in mid-dissection; dead rats are seen.
A man is briefly shown naked and handcuffed to a bed, with only a pillow covering his private parts. He makes a suggestive sexual comment to the chamber maid. Some flirty banter between former lovers, and a few quick kisses exchanged between them. A woman undresses; her naked back is glimpsed.
Very little; extremely infrequent uses of words like "damn" and "hell."
Drinking, Drugs & Smoking
Holmes sometimes drinks to excess (and he isn't always picky about what he drinks to get there); characters drink wine at a restaurant; Holmes smokes a pipe.