Short version: Don't play this game. It is the opposite of good.
It has references for people who enjoyed the book, and that's about all it's got going for it other than not crashing like a Bethesda game. Unless you're a fan of terrible tedious puzzles. Not logic/deduction based, as would be expected of a Sherlock game, but annoying temples of Hanoi type puzzles.
I've never played any of the other Sherlock Holmes games, nor do I know too much about his stories. That said, as a fan of adventure/mystery/thriller games, I had a great time playing this.
This game reminded me of titles like L.A. Noire, Professor Layton and even a bit of Phoenix Wright. You play as both Sherlock and his partner Watson as they put together clues and solve London's most bizarre mysteries. There's absolutely no action or fighting on the player's part whatsoever, but I honestly didn't even care. The story is intriguing and the game hard to put down since you'll keep wanting to know what happens next.
There are, however, a few minor things that keep this game from being amazing. First, and most annoyingly, Sherlock always seems to get stuck in place whenever he opens a door. For a few seconds, I just couldn't move him. I'd wiggle the control stick until he somehow broke free of his paralysis.
Second, some of the puzzles are extremely difficult, and I like challenging puzzles. Worse, the puzzles usually have no instructions. Half the time, you don't know what you're trying to accomplish. Fortunately, you can skip a puzzle if you can't solve it (this will cause you to miss out on an achievement, though).
Graphics are fine, but nothing extraordinary. The sound seems a bit off. Sherlock's footsteps sound too loud at times, and his feet make an odd scraping noise when he turns in place. The same music track seems to play throughout most of the game, but if it annoys you, you can turn it off. The character's voices aren't bad at all.
There's also no autosave, so be prepared to save your game often. I recommend keeping at least two or three backup saves handy just in case.
It's not too long, about 10 hours, maybe more if you don't cheat and look up the puzzle solutions online. In short, the game does have problems, but in a market starved of similar titles, it's at least worth a rent.