In this game, the author introduced some very specific commands that allows the player to enter the mind of Sherlock Holmes. This, I thought, was rather brilliant, such as combining thoughts to create conjectures, or looking up information in Sherlock's vast attic of factual memories.
Where the game falls short is as a puzzle. The player is always told how to proceed, and there were no proper challenges. Ultimately, the player ends up hitching a ride with Sherlock, rather than playing him.
I'd really love to see the same game mechanism used for further Sherlock games, offering a significantly higher difficulty.