Here is the full list of all 38 Pier Solar and the Great Architects achievements.
Used an ability that requires level 5 gather.
Won 600 battles.
Solve the puzzle in Alina's dream on your first attempt.
Defeated the monster living in Teusa.
Unlocked the sound test.
Won 300 battles.
Defeated the Crab at the sanctuary.
Won 100 battles.
Helped the bounty hunter to retrieve his treasure.
Defeated the cave guardian.
Enriched your knowledge by doing tutorials.
Won your first battle.
Helped a hunter in his rabbit hunt.
Received all trophies.
Finished professor Meyer's trials.
Defeated the giant spider.
Defeated Ryan the lion.
Defeated the Metal Robot at Timpo factory.
Defeated Ironhart.
Defeated the bakery chef.
Defeated Sasheer.
Defeated the Ludon excavation guardian.
Defeated Kleoneo.
Defeated Cliboe.
Defeated Bethina.
Did not give up on hope and fought for a better future.
Gave up on hope and sacrificed yourself for a better future for your friends.
Found all spells that can be learned.
Completed Arburus side-quest.
Mastered the slippery game.
Found all master keys.
Found all Sega Genesis cartridges.
Bought all items available in the shops.
Discovered a fragment of another world in yours.
Became a slippery game god.
Collected all the treasures from all chests.
Completed the game fighting only the mandatory battles.
Equipped the best possible items on your characters.