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 B.
Beat all bosses without flask consumption.
Provoke the meeting between Redento and Cleofás.
Witness the last moments of Viridiana.
Cross the Bridge door in less than 3 hours.
Talk with all the corpses.
Get all prayers.
Get 100% of the game.
Get all sword hearts.
Release all cherubs.
Get all rosary beads.
Buy all the items of the Candelaria shops.
Help Cleofás in his path of redemption.
Get all collectibles.
Achieve the maximum value of health.
Achieve the maximum value of flasks.
Achieve the maximum value of fervor.
Achieve the maximum value of rosary bead slots.
Unlock the ending A.
Beat His Holiness Escribar.
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.
Buy all skills from the Mea Culpa shrines.
Achieve the maximum level of the Mea Culpa sword.
Help the Pilgrim reach his final destination.
Beat all the arena challenges.
Use the Righteous Riposte 5 times.
Visit the tomb of The Lady of the Tailed Gown.
Bring all the offerings to Lvdovico.
Save all Kissers of Wounds.
Hatch the Egg of Altasgracias.
Beat Quirce, Returned by the Flames.
Beat Melquíades, The Exhumed Archbishop.
Beat Exposito, Scion of Abjuration.
Beat Esdras, of the Anointed Legion.
Beat the Tres Angustias.
Execute 5 different enemies.
Kill 666 enemies.
Beat Perpetua.
Beat Ten Piedad.
Beat the Our Lady of the Charred Visage.
Beat the Warden of the Silent Sorrow.