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