From the opening to the closing credits, filled with illustrations that originally accompanied Doyle's stories in the Strand, the details of the movie are painstakingly accurate when compared to those in the canon. This is one non-canonical Holmes story that exists in the same world as Sir Arthur Conan Doyle's Sherlock Holmes.
The movie takes the liberty of assuming that all of Dr. Watson's accounts of Sherlock Holmes are true, except for one. That would be "The Final Problem", in which the great detective supposedly dies at the hands of his arch-enemy Professor Moriarty. The movie suggests that this story is merely a cover up for a period in time in which Holmes was getting help with his cocaine addiction from none other than famous psychiatrist Sigmund Freud.
The settings and characters ring true to both Doyle's mysteries and the Sydney Paget illustrations that accompanied them. Sherlock Holmes' deerstalker and cloak, though never mentioned by Doyle, look more like Paget's illustrations than ever before, more rugged than in most film interpretations. American actor Robet Duvall, despite sometimes struggling with the British accent, portrays Watson as an intellectually and physically fit comrade for Holmes, not a bumbler. Laurence Olivier's Prof. Moriarty matches the vision of Doyle and Paget rather than the cliché mustache twirler of other movies. Only now, Moriarty isn't really a criminal mastermind. He's Holmes' childhood math tutor.
Alan Arkin depicts Freud as a man of intelligence, insight, and above all, honor.
The inclusion of lesser known characters like Mycroft Holmes and Toby is a plus. There are also references, both direct and sly, to canonical Holmes stories.
While Nicol Williamson's performance as Sherlock Holmes lacks the vigor and spark of Basil Rathbone or Christopher Plummer, Williamson succeeds in showing Holmes as a troubled individual rather than a god. The movie mixes drama, subtle humor, mystery, and even action, finally showing Holmes as the capable fighter he was in the canon. The end of the film strays from the books in order to explore the uncharted territory of Holmes' childhood, providing a deeply moving climax.
This may come truer to Sir Arthur's original vision than any other pastiche written for film so far, largely thanks to the efforts of writer/director Nicholas Meyer. It's obvious in every scene that Meyer has a great love for the writings of Arthur Conan Doyle.
