One of the things I found to be very fun about this movie is how it implemented the fiction of Arthur Conan Doyle into the world of 19th century London. The environments of industrial London are very well designed and the fan service for Sherlock fans is, admittedly, a pretty fun treat. The movie felt a lot more like an action-adventure story than the usual "stay-in-one-place" murder stories in most movies.
One of the things that I originally didn't liked was the perpetrators motivation to trap all of the children under threat of death. Even now when I do understand what he really meant to do, it still feels kind of weird, ya know? You don't just go saying things like that only to reveal that you meant completely different. Among other criticisms, the fact that the whole movie takes place inside a game is pretty silly, I thought Yusako's case in the real world was basic(the fact that he had to wait for Conan to reveal the culprit's motive was contrived), most of the dialogue is pretty clumsy and hammy(e.g., the villain revealing his goal), and how there is barley any lack of tension when one of the characters gets offed in the game.
My criticisms may look many, but I assure you that this movie is still quite good. If you just choose to let things be as they are and not worry too much about it, then The Phantom of Baker Street can still be a fun, good time.
