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