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.
Beat all the arena challenges.
Help Cleofás in his path of redemption.
Discover all zones.
Beat Crisanta of the Anointed Blade.
Beat Quirce, Returned by the Flames.
Beat all types of enemies.
Help the Pilgrim reach his final destination.
Beat Melquíades, The Exhumed Archbishop.
Beat Exposito, Scion of Abjuration.
Beat Esdras, of the Anointed Legion.
Kill 666 enemies.
Beat Ten Piedad.
Execute 5 different enemies.
Beat the Tres Angustias.
Beat Perpetua.
Visit the tomb of The Lady of the Tailed Gown.
Beat the Our Lady of the Charred Visage.
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 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.
Use the Righteous Riposte 5 times.
Bring all the offerings to Lvdovico.
Witness the last moments of Viridiana.
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.
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.