Here is the full list of all 46 Ys Origin achievements.
Unlock all other achievements.
Complete Boss Rush on Nightmare difficulty with all versions of all characters.
Complete four or more consecutive stages in Arena Mode without taking any damage.
Complete any Arena stage with less than 10 HP.
Unlock Yunica's schoolgirl outfit.
When playing as neither Yunica nor Hugo, completely refrain from using Burst until the final encounter.
Obtain all blessings/upgrades with all characters.
As Hugo, obtain ultimate power... then let it go to waste completely.
As Hugo, emerge victorious during your emotional encounter in the Guilty Fire.
Complete Boss Rush on Easy difficulty with any character.
Complete Boss Rush on Normal difficulty with any character.
Complete Boss Rush on Hard difficulty with any character.
Complete Boss Rush on Nightmare difficulty with any character.
Fight all enemies (excluding bosses) enough times to fill in all blank data entries for them in your monster journal.
As Yunica, persevere against an unbeatable foe in the Guilty Fire.
Unlock every character's EX version.
Purchase everything available in the Bonus Shop.
Unlock any character's EX version.
Unlock Adol the Red in the Bonus Shop.
Fight and defeat Pikkardon in Arena Mode.
Spend more than 2,000,000 SP in the Bonus Shop.
Complete the game on Nightmare difficulty with all characters.
Enable "No-Fall" mode for the first time.
Defeat the final boss and obtain the game's true ending.
Defeat the Demonic Core end boss with all playable characters.
As Hugo, defeat Toal; as Toal, defeat Hugo.
Defeat the mid-boss in the Hall of Reflection with all playable characters.
Give Roda Fruit to all of the Roos in the tower with every character.
Defeat the Blighted Blood end boss with all playable characters.
Defeat the Silent Sands end boss with all playable characters.
Defeat the Guilty Fire end boss with all playable characters.
Defeat the Flooded Prison end boss with all playable characters.
Defeat the Wailing Blue end boss with all playable characters.
Complete the game as Hugo.
Complete the game on Nightmare difficulty with any character.
Thwart the Darkling lackeys in the Demonic Core as both Yunica and Hugo.
Defeat the mid-boss in Rado's Annex as both Yunica and Hugo.
Thwart Epona's early-game challenges as both Yunica and Hugo.
Obtain all blessings/upgrades with any character.
Complete the game as Yunica.
Unlock Toal by completing the game as Yunica or Hugo.
Complete the game on Very Easy difficulty with any character.
Complete the game on Easy difficulty with any character.
Complete the game on Normal difficulty with any character.
Complete the game on Hard difficulty with any character.
Purchase your first blessing/upgrade.