I hated the game. I wish I could understand why it was popular. I thought the game would be like solving puzzles related to the mystery, trying to work your way through to find out what was going on.
Instead the puzzles were pretty much in the 'WTF?' category. PL&TCV was really just a book of random puzzles that had nothing to do with the story. I struggled through the game but I could only do two or three puzzles in one sitting before I got extremely bored and moved on.
I did finally finish it though... and sold it to someone else for $20. I don't plan on getting the sequel; Professor Layton and The Diabolical Box.