Here is the full list of all 45 Blasphemous achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Get 100% of the game.
Get all prayers.
Talk with all the corpses.
Release all cherubs.
Achieve the maximum value of fervor.
Get all rosary beads.
Get all collectibles.
Get all sword hearts.
Bring all the offerings to the Blessed Lord of Salty Shores.
Get all relics.
Visit the tomb of The Lady of the Tailed Gown.
Bring all the offerings to Lvdovico.
Help Cleofás in his path of redemption.
Buy all skills from the Mea Culpa shrines.
Achieve the maximum level of the Mea Culpa sword.
Unlock the ending A.
Achieve the maximum value of rosary bead slots.
Beat all the arena challenges.
Unlock the ending B.
Beat His Holiness Escribar.
Beat all types of enemies.
Discover all zones.
Beat Crisanta of the Anointed Blade.
Beat Melquíades, The Exhumed Archbishop.
Achieve the maximum value of health.
Achieve the maximum value of flasks.
Beat Quirce, Returned by the Flames.
Help the Pilgrim reach his final destination.
Hatch the Egg of Altasgracias.
Beat Exposito, Scion of Abjuration.
Buy all the items of the Candelaria shops.
Beat Esdras, of the Anointed Legion.
Witness the last moments of Viridiana.
Beat the Tres Angustias.
Execute 5 different enemies.
Use the Righteous Riposte 5 times.
Beat the Our Lady of the Charred Visage.
Kill 666 enemies.
Beat Ten Piedad.
Beat the Warden of the Silent Sorrow.
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.