I must begin by saying that full 3D is a very bad idea for adventure games. Being a genre which relies on skills of observation and logical thinking, rather than twitch reflexes, 3D is too much. It quite literally makes me ill. Every few steps, you are constantly scrutinising your surroundings for clues, rotating and panning the camera to check every angle. Actions which we can do quite naturally in real life, are rather dizzying when reproduced on screen. It may sound like a minor grievance but it is not. I was unable to experience the game as fully as I would have liked, as I had to resort to a walkthrough early on to save myself from eye-strain induced migraines. It does not bode well for a game if it makes you ill to play. The node-based 3D utilised by Myst and its many clones would have been quite adequate, as it focuses your attention to specific areas. It is a shame, but they seem to have gone too far in trying to immerse the player, and forgetting that first and foremost, it is a game.
Still, moving on to the gameplay; it's a bit of a mixed bag to be honest. Some puzzles seem to be the 3D equivalent of pixel hunts requiring a keen eye and careful positioning to spot useful items and clues. Some puzzles were intuitive and rather clever, some were tough but made sense when you knew the answer, and a few were 'How on earth could I have known that!?'. The last applies particularly to a game feature that I also have mixed feelings on.
At various points in the game, Sherlock asks you (as Watson) a question regarding the case and which direction it should take, before you can proceed. You must enter the question into a parser so there's no clicking through multiple choice until you get the right one. Some were straightforward and just require you to review case information (like the first instance of this feature), but others require information not available in game, or huge leaps of deduction. It's alright for Holmes to figure out such things, but Watson is not quite so accomplished. One question required you to decipher a numerical code with no guidance whatsoever! It would have been a nice gimmick if it were used better, like in it's first instance, where it encourages you to think about and involve yourself in the case, rather than randomly clicking through it as so often happens with adventure games.
Gameplay issues aside, the story is kind of worth the effort. Investigating the disappearance of a neighbour's servant leads Holmes and Watson on the trail of a murderous cult. It is dark and disturbing, and not for the faint of heart. I can't fault the atmosphere as it gave me the 'heebie jeebies' at various points in the game. Though the graphics may not be photo-realistic, scenes of a nude body hacked up and spread over a bloody altar are unnerving to say the least.
The characters are absolutely delightful. Holmes with his understated arrogance and superiority complex, and Watson fumbling along in the dark trying to keep up. Though there are many characters that are seen only briefly, they do not seem at all shallow.
So overall, it's a game with an intriguing story and well-done characters, but let down by inconsistent puzzles and gameplay issues. If you enjoy sleuthing games, it's worth your while checking it out, but you may want to keep a walkthrough close at hand.