I'd like to introduce the most important part of the game:

The translating system.

First, a piece of music would be disassembled into instrument tracks. You need to find out motives inside the tracks.

Once you find one, you mark it by holding "M" when it is played. The motive detector shall detect it if you have successfully marked one.

Then you select a motive from the upper displayer to match with it.

Then press "E" to judge whether the marked motive and the displaying one is matched. If you did it correctly, the green light shall be on.

Each motive carries a certain feeling, event or person. Thus whenever you match one you would unlock a piece of story. Then the story would be added to the codebook, which also records the motives you have met.

This is basically how the translating system works.