Note: This game is also titled Layton Kyouju To Akuma No Hako.
Prequel bonus
Insert Professor Layton And The Curious Village, and have a completed saved game file with at least 129 puzzles solved. At the main menu, select the "Bonuses" option, then select the completed saved game. Choose the "Top Secret" option, then select "The Hidden Door" option. Make a note of the eight character code displayed on "The Hidden Door Of St. Mystere" screen. This code is randomly generated and varies between game systems. Turn off the system, and insert Professor Layton And The Diabolical Box. At the main menu, select the "Bonuses" option, then select any game file. Choose the "Top Secret" option, then select "The Hidden Door" option. Choose "The Secret Of The Elysian Box" option. Enter the password obtained from Professor Layton And The Curious Village to unlock "Curious Present: The Secret Puzzle No.???". Solve this puzzle to see a picture of Professor Layton and Luke from their first adventure.
Completion bonuses
Successfully complete the game with the indicated number of Picarats to unlock the corresponding option(s) at the "Top Secret" menu:
Character Profiles: 2,500 Picarats
Character Voices: 4,000 Picarats
Game Music: 3,500 Picarats
Movies: 4,500 Picarats
Story Art: 3,000 Picarats
Final page of profiles: 5,500 Piccarats
Bonus puzzles
Successfully complete the indicated task to unlock the corresponding set of puzzles:
The Musicians House - Puzzles 139 to 141: Collect all 10 Strange Camera pieces to make the camera. Take all nine photos with the camera, then find the three differences in each picture.
the Tea Master's House - Puzzles 142 to 144: Get all tea ingredients to find the different tea brews. Give the correct tea brew to all 28 people in need.
The Animal Lover's House - Puzzles 145 to 147: Get the hamster's fatness level down to 0. It takes 30 steps in a row to get the hamster to lose all the extra weight.
The Sweetheart's House - Puzzles 148 to 150: Successfully complete the main game.
Puzzles 151 to 153: Successfully complete puzzles 1 to 150.
Golden saved game icons
Successfully complete the indicated task to unlock the corresponding gold icon next to your saved game file:
Flora with Layton's hat: Successfully complete all 153 puzzles.
Layton: Successfully complete the game.
Luke: Successfully complete all puzzles in Story mode.
Easy Hint Coins
Successfully complete the Hamster mini-game. The hamster will find Hint Coins.
Free hints
Save the game before attempting a puzzle. Use Hint Coins to view all the hints, then reload the saved game to solve the puzzle without using any Hint Coins.
Tea recipes
Combine the indicated ingredients to create the corresponding tea:
1. Belle Classic: Oasis Leaf, Brisk Berry, Belle Tart Seed