On the Choose Slot screen, First HIghlight a saving slot then rapidly press UP-UP-DOWN-DOWN-LEFT-RIGHT-LEFT-RIGHT-B-A.
A validation sound should play if the manipulation was successful.

How to Unlock or lock some levels?
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[ONLY WORKS WHEN DEBUG MODE IS ACTIVATED]

On any Choose Level Screen, press the L button to reduce the number of unlocked levels by 1, and press the R button to increase it.

How to unlock all of the workshop activities?
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[ONLY WORKS WHEN DEBUG MODE IS ACTIVATED]

On the workshop map screen, press the R button.

How to navigate between the workshop map and the house map?
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[ONLY WORKS WHEN DEBUG MODE IS ACTIVATED]

On the workshop map screen, press the L button to switch to the house map.
On the house map screen, press the L button to switch to the workshop map.

How to unlock all the moves?
----------------------------

[ONLY WORKS WHEN DEBUG MODE IS ACTIVATED]

Use the L button in the garden.

How to unlock all backgrounds in the Photostudio ?
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[ONLY WORKS WHEN DEBUG MODE IS ACTIVATED]

Use the L button in the photostudio.

How to unlock items in the Store ?
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[ONLY WORKS WHEN DEBUG MODE IS ACTIVATED]

Use the L button in the dressing-room.