Here is the full list of all 12 Shuffle! achievements.
Watched the first opening movie.
Opened the gallery.
Started the game.
Completed the Lisianthus route.
Completed Lisianthus's True Ending
Completed the Nerine route.
Completed the Kaede Fuyo route
Completed the Asa Shigure route.
Completed the Primula route.
Completed the Kareha route
Completed the Mayumi Thyme route.
Completed the gallery.