Professor Layton, being the intelligent puzzle master he is, leaves to Luke some extra and quite difficult puzzles for the player to complete after you complete each installment of the Professor Layton series. These difficult puzzles give you 50 to 99 Picarats and are known as Layton's Challenges.
The player unlocks one of the five "houses" (containing three puzzles) whenever you meet the certain criteria. For the first three you must beat the respective mini games. For the bottom two you must finish the main storyline for the game and you must complete every puzzle in the game excluding the three within the last house.
Professor Layton and the Curious Village
The Inventor's House
The Decorator's House
The Art Lover's House
The Golden Apple's House
The Puzzle Master's House
Professor Layton and the Diabolical Box
The Musician's House
The Tea Master's House
The Animal Lover's House
The Sweethearts' House
The Puzzle Doctor's House
Professor Layton and the Unwound Future
The Storyteller's House
The Hotelier's House
The Messenger's House
The Time Traveler's House
The Puzzle Keeper's House
Professor Layton and the Last Specter
The Boatman's House
The Biologist's House
The Puppeteer's House
The Flute Player's House
The Puzzle Keeper's House
Professor Layton and the Miracle Mask
