Unfortunately, it's not. 

Prometheus is visually stunning, there's no question about it, and has some of the very best 3D I've seen, even comparing quite favorably to the gimmicky 3D James Cameron used in Avatar. The story is epic, and revolves around one of the most fundamental questions we humans have, something that goes back as far as we have told stories: who are we and where did we come from?

The problem is that there's insufficient narrative thread to weave together everything that happens in the film, and much more importantly, there are a large cast of characters who are generally inexplicable. Why are they doing what they're doing? Why do some characters, like tough guy Fifield (Sean Harris) change personality halfway through the film? Android David (superbly played by Michael Fassbender) is perhaps the most inexplicable of all. With an obvious nod to the malevolent computer HAL from the great 2001: A Space Odyssey, David behaves in ways that were frequently baffling.

The film opens in the mid 21st Century with anthropologists discovering cave paintings in northern Great Britain, paintings that share common elements with others discovered throughout the world. But the civilizations never interacted: how can the paintings have similar elements? Putting the clues together, they identify a far distant planet in another galaxy, a planet that has an Earth-like atmosphere. Is that the origin of mankind?

The spaceship Prometheus is built and its crew, other than David, is kept in stasis. When they awaken in a ship with clear visual nods to the Nostromo from Alien, we meet lead scientists Shaw (Noomi Rapace) and Holloway (Logan Marshall-Green), along with the detached corporate representative Vickers (Charlize Theron), Prometheus captain Janek (Idris Elba), another dozen or so crew members and even a holographic elder statesman and mission sponsor Peter Weyland (Guy Pearce, wasted in a role with so much prosthetics).

In the original books by Arthur Conan Doyle, Sherlock Holmes is a fastidious, rather odd bird with extraordinary knowledge and powers of observation. Famously able to deduce things from the tiniest speck of dust or wrinkle in a hem, he was the anti-hero, someone who was generally unlikeable but brilliant. Reimagined by directory Guy Ritchie and action star Robert Downey Jr. (think Iron Man), Holmes is completely different in A Game of Shadows and looks more like a homeless vagabond than a celebrated detective.

As with the books, the narrative is from the perspective of his long-suffering companion and friend Dr. John Watson (Jude Law), who applies his medical background and experience to aid in solving particularly perplexing mysteries. Except in A Game of Shadows, there's not much mystery, there's not really a case, there's no client, and the story unfolds in an increasingly baffling and incoherent manner.

The story revolves around Holmes uncovering a plot by the nefarious Professor James Moriarty (Jared Harris) to start a world war and then profit by selling arms and ammunition to both sides. Holmes rival and love interest Irene Adler (Rachel McAdams) appears for a short time, to be replaced on screen with the more interesting Gypsy fortune teller Madame Simza (Noomi Rapace). Watson has just married Mary (Kelly Reilly) and it's during their honeymoon that Holmes intervenes in a plot by Moriarty to murder Watson, conveniently sidetracking Mary for the rest of the film and forcing Watson to reluctantly take on this, their last case together.

The special effects are impressive, but even there the innovations of the first film are overused in this sequel to the point where it's bizarre and at one point even breaks the narrative wall. Near the end of the film, Holmes plots out the specific moves he'll use in a fight against arch-enemy Professor James Moriarty (Jared Harris), who then looks at Holmes and says "two can play at that, sir" and similarly plots out, in graphic slow motion, his anticipated moves in the upcoming scuffle. But how does Moriarty know that Holmes was figuring out his attack?

I've always been a fan of the enigmatic, brilliant Sherlock Holmes, but I think that from a cinematic and narrative perspective Sherlock Holmes: A Game of Shadows leaves a lot to be desired. It's visually pretty, but there's much that doesn't make sense and Ritchie and Downey have created a completely new Holmes that has nothing to do with the fictional creation of Doyle and while it's entertaining, it's also overly long, tedious and confusing as heck. I'd wait until it's on DVD and make sure you've got some popcorn to munch on during the overly long later scenes.