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