Update - 27 November 2023

In addition to the following changes, there is an alternate version of the game using traditional Christmas music. This includes 25 new puzzles and makes better use of the "Major/Minor Key Change" option.

Major Changes

Added 11 new puzzles (1 practice, 3 easy, 5 medium, and 2 hard).

Added two new chiptune-style instruments.  Added a instrument with a combination of vibrato and decay.  This instrument improves the sound of songs that use long-duration notes.  This sound of the organ instrument has also been improved (the lower pitched harmonics are louder and repeated notes will sound more distinct).

Puzzles can now specify a preferred instrument.  Songs that sound better with a particular instrument will default to it.  For an example, see the new easy puzzle "心臓がとまるまで" which prefers an instrument with less sustain.

Improved UI flow.  The currently selected song and the "Generate Puzzle" button are more prominent.  Customization controls are disabled by default to avoid pushing the complexity at new players.

Improved note-reversal algorithm.  The previous version would reverse the chord as a single unit.  When a song contained two notes played at the same time of different durations, this could produce unexpected results.  Now each of the notes is reversed individually.

Minor Changes

Added additional symbols for 'Blind' challenge mode.

Fixed a bug where solving an already solved puzzle did not return you to the main menu.