World Ends With You, The Cheats (Nintendo DS)

Successfully complete the game, and save when prompted. You can start a new session with
your cleared saved game file with most of your previously obtained items and skills.
There will be an option to select any chapter to replay with bonus objectives at the
cellphone menu. You can now select "A New Day" chapter and go to Shiba-Q Headquarters. At
the third floor, you can purchase the Ultimate difficulty as a quest item. The "Another
Day" chapter will appear at the chapter selection menu.

Collect all of the secret reports, including the one in Another Day, to view a bonus scene
after defeating the final Boss in the main story.

When you save and turn off the Nintendo DS, you will gain PP points for the pins you have
on. You can use this to your advantage by changing the system date. Save your game, turn
off the Nintendo DS, turn it back on, go to the date setting, then set it forward by
seven days. The Nintendo DS will turn itself off after you are done. Turn it back on, and
load your game. You should gain PP points for seven days. Repeat this as many times as
desired. Once done, save the game, and change the date back to the correct value.

Successfully complete the game on the Normal difficulty to unlock the Hard difficulty.

Successfully complete the indicated task to unlock the corresponding character icon at the
saved game screen:

Beat: Successfully complete the third week.

Joshua: Successfully complete the second week. 

Mr. Hanekoma: Collect all secret reports.

Mr. Mew: Get 100% Pin Mastery.

Rhyme: Collect all items. 

Rhyme (noise form): Successfully complete the noise list. 

Shiki: Successfully complete the first week.

At the save data menu, hold L + R.