Guy Ritchie directs his films like a bar fight. If his heroes aren’t being literally knocked about, their best-laid plans certainly are. “Sherlock Holmes” is no exception.

Ritchie keeps all of the famous detective’s formidable intelligence but chips off the Victorian polish. Holmes (Robert Downey Jr.) blows off steam boxing in seedy London fighting pits, frequently drugs Dr. Watson’s (Jude Law) dog to test potions that criminals may have used (the housekeeper, at one point, exits his room with the observation, “He’s killed the dog…again.”), and is discovered by a hotel chambermaid, tied to a bed, buck naked, with the only accommodation to propriety being a strategically placed pillow. This is not Sherlock Holmes as Sir Arthur Conan Doyle originally conceived him, but he is a lot of fun and Robert Downey Jr. plays him with relish—as a brilliant man whose exertions to keep up with his own high-revving intelligence have left him a little unhinged.

While Robert Downey Jr.’s Holmes may have no internal gyroscope, he does have Dr, Watson. “Sherlock Holmes” is a buddy movie in the best sense of the word and Jude Law creates a fine-tuned chemistry with Downey. As he demonstrated in “Cold Mountain,” Law has a genius for channeling potent performances through quiet men. His Dr. Watson is as comfortable with the constraints of Victorian mores as Holmes is disdainful of them and he often creates the perfect editorial comment on Holmes’ shenanigans with little more than a look. The expression of horror on his face when his fiancé, Mary (played by the exquisite Kelly Reilly), innocently asks Holmes to use his legendary powers of observation on her steals the scene.

If the film has any weakness, it is in the script. Holmes and Watson break up what was to be a ritualistic murder during some kind of cult ceremony and capture the notorious serial killer, Lord Blackwood (Mark Strong who was magnificent as the Jordanian Intelligence chief in “Body of Lies”—this is a film that doesn’t scrimp on talent). Lord Blackwood proves a tougher man to stop than they had bargained for and the case soon leads into secret societies and political intrigue that threatens the very heart of the British government.

The plot isn’t bad, just bloated. It has that same cobbled-together-for-a-blockbuster feel as the script of “National Treasure.” Considering the film’s other perfections you soon long for a script with the same dark, comic bite as Ritchie’s earlier movies such as “Lock, Stock and Two Smoking Barrels” or “Snatch.” His exceptional cast deserves that much.

Especially Rachel McAdams who fogs Holmes’ thinking as the sultry Irene Adler, Sherlock’s sometime girlfriend and sometime criminal nemesis. McAdams has long ago proven that she can keep up with any actor in Hollywood but she isn’t given a lot to work with here.

Whatever wistful aftertaste the script may leave is soon washed away by the good-natured exuberance of the film. There are a lot of very talented people having a lot of fun with this project. Ritchie’s CG team creates a deliciously grimy industrial London to match his scruffy Holmes and the actors are, universally, better than the lines they’re given.

This may not be the best Sherlock Holmes film ever made but it is one of the most entertaining.