Here is the full list of all 38 Thymesia achievements.
Craft a potion recipe for the first time
Fully upgrade a potion.
Collect all potion ingredients.
Craft all potion recipes.
Collect all lore.
Collect all entries in the collection.
Empty the first health bar of Varg in the tutorial.
Defeat any boss without using potion.
Break 1000 barrels.
Reach max level.
Unlock all achievements.
Fully upgrade a plague weapon for the first time.
Unlock all plague weapons.
Reach the "Power of Cleasing" ending.
Reach all endings.
Reach the "Chaotic Power" ending.
Reach the "Harmonized Force" ending.
Reach the "Power of Vile Blood" ending.
Reach the "Blessing of Pure Blood" ending.
Finish all levels.
Defeat Corvus.
Defeat Urd.
Collect all story bits.
Finish "Hermes Fortress" level.
Defeat Varg.
Defeat Sound of the Abyss.
Finish "Royal Garden" level.
Defeat The Hanged Queen.
Defeat Mutated Odur.
Defeat God of the Fools.
Finish "Sea of Trees" level.
Defeat Odur.
Unlock a plague weapon for the first time.
Start recalling for the first time.
Finish the tutorial.
Dead for the first time.
Rest at the beacon for the first time.
Reave a plague weapon for the first time.