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