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