Here is the full list of all 9 Pretty Girls Rivers (Shisen-Sho) achievements.
Played the game for the first time.
Clear one stage.
Clear all RICHE stages in normal mode.
Clear all REIU stages in normal mode.
Clear all KANON stages in normal mode.
Clear all REN stages in normal mode.
Clear all CECIL stages in normal mode.
Clear all RISA stages in normal mode.
Clear all 6 character stages in normal mode.