First thing to say about this game is that, yes, it is very addictive and you will probably want to complete it all straight away. However, if you want a detective game, where you can make accusations and prevent any more murders, this is not it. You are guided through each task with little variation from the prescribed gameplay except in the final scene. I certainly got frustrated that I couldn't alter the course of events and that I couldn't express my suspicions or investigate certain aspects further, although this is probably too much to expect from a PC game.
That being said, the game is enjoyable in having to use your wits in order to complete each section. The ending is ok, but less believable than the original book. Highly enjoyable, but don't expect to lead the story. Just go with the flow, it's still good fun!