Here is the full list of all 45 Blasphemous achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Buy all skills from the Mea Culpa shrines.
Buy all the items of the Candelaria shops.
Unlock the ending B.
Beat His Holiness Escribar.
Beat all types of enemies.
Achieve the maximum value of health.
Help the Pilgrim reach his final destination.
Achieve the maximum level of the Mea Culpa sword.
Hatch the Egg of Altasgracias.
Discover all zones.
Beat Crisanta of the Anointed Blade.
Visit the tomb of The Lady of the Tailed Gown.
Beat Quirce, Returned by the Flames.
Beat Exposito, Scion of Abjuration.
Witness the last moments of Viridiana.
Beat Melquíades, The Exhumed Archbishop.
Execute 5 different enemies.
Beat Esdras, of the Anointed Legion.
Beat the Tres Angustias.
Kill 666 enemies.
Beat the Our Lady of the Charred Visage.
Beat Ten Piedad.
Beat the Warden of the Silent Sorrow.
Unlock the ending A.
Release all cherubs.
Talk with all the corpses.
Beat all the arena challenges.
Get all prayers.
Get all relics.
Get all rosary beads.
Get all collectibles.
Get all sword hearts.
Achieve the maximum value of fervor.
Achieve the maximum value of flasks.
Achieve the maximum value of rosary bead slots.
Use the Righteous Riposte 5 times.
Bring all the offerings to Lvdovico.
Help Cleofás in his path of redemption.
Bring all the offerings to the Blessed Lord of Salty Shores.
Save all Kissers of Wounds.
Beat Perpetua.
Provoke the meeting between Redento and Cleofás.
Beat all bosses without flask consumption.
Cross the Bridge door in less than 3 hours.
Get 100% of the game.