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.
Cleared the game on Nightmare difficulty.
Acquired at least one of every item.
Proved your skill as a merchant.
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.
Filled out all monster details in journal.
Restored all lost memories.
Completed the main story.
Overcame Gruda's trial.
Played extensively as Karna.
Played extensively as Duren.
Played extensively as Frieda.
Enhanced a weapon or armor to its limit.
Filled out all material details in journal.
Amassed one million gold.
Mastered every skill.
Played extensively as Ozma.
Defeated the ruler of the Great Forest.
Befriended all animals.
Found all of Mishy's hiding spots.
Opened every treasure chest.
Discovered every resource point.
Played extensively as Calilica.
Opened the door to the Temple of the Sun.
Successfully completed every quest.
Defeated a rare golden foe.
Endured all of Zara's tickle sessions.
Purchased every piece of info from Mouse.
Played extensively as Adol.
Completed the Map of Celceta.
Acquired both halves of the Mask of the Moon.
Walked an extraordinary total distance.
Cleared all obstructed paths.
Arrived in the ruined capital, Elduke.
Defeated two thousand enemies.
Located the underground village of Danan.
Successfully used Flash Move fifty times.
Reunited with Eldeel at the Tower of Providence.
Successfully arrived in the Primeval Lands.
Achieved five hundred Skill Finishes.
Successfully used Flash Guard fifty times.
Achieved one thousand Aerial Combos.
Achieved five hundred Excellent Kills.
Resolved the polluted river dilemma.
Defeated Duren in one-on-one combat.
Solved the mystery of the missing villagers.
Discovered a settlement in the Great Forest.
Successfully rescued the trapped miners.
Began your adventure in Celceta.