Here is the full list of all 52 Ys: Memories of Celceta achievements. It takes around 50-60 hours to unlock all of the achievements on Windows.
Acquired all achievements.
Conquered Boss Rush.
Conquered Boss Rush without a single retry.
Defeated a boss in Time Attack without taking damage.
Defeated a boss in Time Attack in thirty seconds or less.
Opened every treasure chest.
Restored all lost memories.
Completed the main story.
Cleared the game on Nightmare difficulty.
Filled out all monster details in journal.
Acquired at least one of every item.
Overcame Gruda's trial.
Played extensively as Ozma.
Mastered every skill.
Defeated the ruler of the Great Forest.
Played extensively as Frieda.
Opened the door to the Temple of the Sun.
Successfully completed every quest.
Played extensively as Calilica.
Enhanced a weapon or armor to its limit.
Amassed one million gold.
Filled out all material details in journal.
Endured all of Zara's tickle sessions.
Discovered every resource point.
Completed the Map of Celceta.
Played extensively as Karna.
Defeated a rare golden foe.
Purchased every piece of info from Mouse.
Acquired both halves of the Mask of the Moon.
Cleared all obstructed paths.
Found all of Mishy's hiding spots.
Played extensively as Adol.
Arrived in the ruined capital, Elduke.
Defeated two thousand enemies.
Walked an extraordinary total distance.
Played extensively as Duren.
Befriended all animals.
Located the underground village of Danan.
Proved your skill as a merchant.
Reunited with Eldeel at the Tower of Providence.
Successfully arrived in the Primeval Lands.
Resolved the polluted river dilemma.
Achieved one thousand Aerial Combos.
Achieved five hundred Excellent Kills.
Defeated Duren in one-on-one combat.
Solved the mystery of the missing villagers.
Achieved five hundred Skill Finishes.
Discovered a settlement in the Great Forest.
Successfully used Flash Move fifty times.
Successfully used Flash Guard fifty times.
Successfully rescued the trapped miners.
Began your adventure in Celceta.