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