Here is the full list of all 26 The Quintessential Quintuplets - there are Five Memories Spent With You achievements.
Unlocked all Achievements.
"Nakano Ichika Route" Normal Ending
Viewed the good ending for the "Nakano Ichika Route."
Viewed the normal ending for the "Nakano Nino Route."
Viewed the good ending for the "Nakano Nino Route."
Viewed the normal ending for the "Nakano Miku Route."
Viewed the good ending for the "Nakano Miku Route."
Viewed the normal ending for the "Nakano Yotsuba Route."
Viewed the good ending for the "Nakano Yotsuba Route."
Viewed the normal ending for the "Nakano Itsuki Route."
Viewed the good ending for the "Nakano Itsuki Route."
Viewed the good ending for "Nakano Ichika" on "All Route."
Viewed the good ending for "Nakano Nino" on "All Route."
Viewed the good ending for "Nakano Miku" on "All Route."
Viewed the good ending for "Nakano Yotsuba" on "All Route."
Viewed the good ending for "Nakano Itsuki" on "All Route."
Viewed the normal ending for "All Route."
Selected a confession target.
Confessed to all quintuplets.
Viewed the tutorial.
Viewed the endings of all quintuplets (regardless of normal ending or good ending) and unlocked "All Route."
Viewed all endings.
Completed the entire SCENE GALLERY.
Completed the entire CG GALLERY
Completed the entire SOUND GALLERY.
Completed the entire MOVIE GALLERY.