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