Here is the full list of all 45 Blasphemous achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Achieve the maximum level of the Mea Culpa sword.
Bring all the offerings to the Blessed Lord of Salty Shores.
Get all relics.
Hatch the Egg of Altasgracias.
Help the Pilgrim reach his final destination.
Unlock the ending B.
Beat His Holiness Escribar.
Beat Crisanta of the Anointed Blade.
Beat all types of enemies.
Beat Exposito, Scion of Abjuration.
Buy all the items of the Candelaria shops.
Beat Quirce, Returned by the Flames.
Witness the last moments of Viridiana.
Beat Melquíades, The Exhumed Archbishop.
Discover all zones.
Beat Esdras, of the Anointed Legion.
Beat the Tres Angustias.
Kill 666 enemies.
Beat the Our Lady of the Charred Visage.
Use the Righteous Riposte 5 times.
Execute 5 different enemies.
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 rosary beads.
Get all collectibles.
Get all sword hearts.
Achieve the maximum value of health.
Achieve the maximum value of fervor.
Achieve the maximum value of flasks.
Achieve the maximum value of rosary bead slots.
Visit the tomb of The Lady of the Tailed Gown.
Bring all the offerings to Lvdovico.
Help Cleofás in his path of redemption.
Save all Kissers of Wounds.
Beat Perpetua.
Buy all skills from the Mea Culpa shrines.
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.