Here is the full list of all 50 Atelier Lydie Suelle The Alchemists and the Mysterious Paintings achievements.
Ascertained the bond between the twins.
Saw a marvelous puppet show.
Defeated the guileless Licensed Alchemist.
Collected all insect materials.
Tricked Lucia.
Corneria has grown.
Had a reunion you have dreamt about.
Repainted surroundings during a battle.
Saw a surprising scene of Hagel and Pamela.
Defeated an ancient God of Thunder.
Got help from "one" who had certainly grown up.
Saw a very happy Firis.
A mysterious happening occurred during a battle in the painting world.
Used Battle Mix for the first time.
Customized a weapon for the first time.
Begun the exploration of a mysterious painting.
Failed in synthesis in the atelier.
Performed a Character Change for the first time.
Unlocked All Achievements.
Reached S Rank.
Reached Normal Ending.
Reached Good Ending.
Reached Shop Ending
Reached Mysterious Painter Ending.
Reached True Ending.
Enjoyed a vacation.
Attended a coronation ceremony.
Was treated to a wonderful potato stew.
Gave Plachta a massage.
Witnessed heavy drinkers.
Witnessed weak drinkers.
Saw to a reconciliation of old friends.
Inspected great many barrels.
Created all weapons and armors.
Spent a lot of money in Corneria's shop.
Collected all fish materials.
Used all patterns of the Battle Mix.
Saw all the Combination Arts.
Created an unbelievable item using the Extra Mix.
Finished many Quests.
Fulfilled all Ambitions.
Discovered all recipes.
Synthesized all items.
Reached max battle level.
Reached max alchemist level.
Played with a fire dragon.
Defeated the core of Remplir.
Defeated the Creator deity.
Defeated the girl who lives in the dark red world.
Defeated the two goddesses who unleashed their full strength.