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