Here is the full list of all 17 Ys I Chronicles+ achievements. It takes around 15-20 hours to unlock all of the achievements on Windows.
Master every achievement in Ys I.
Unlock all details for all non-boss bestiary entries.
Completely fill the character notebook.
Level-up Feena.
Make Dogi break through three different walls.
Complete Ys I Time Attack.
Complete Ys I on any difficulty.
Complete Ys I on Nightmare difficulty.
Rescue Luta Gemma from monsters in the field.
Max out your money.
"Measure" Feena in the creepiest way possible.
"Measure" Feena.
Confuse and astound the townsfolk.
Listen to Reah recite her poem.
Receive a free Talwar prior to entering the tower.
Drive a hard bargain with Pim.
Receive a free Short Sword.