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