Here is the full list of all 45 Blasphemous achievements. It takes around 25-30 hours to unlock all of the achievements on Windows.
Use the Righteous Riposte 5 times.
Beat all bosses without flask consumption.
Provoke the meeting between Redento and Cleofás.
Save all Kissers of Wounds.
Cross the Bridge door in less than 3 hours.
Unlock the ending A.
Get 100% of the game.
Talk with all the corpses.
Get all prayers.
Release all cherubs.
Get all rosary beads.
Beat all the arena challenges.
Get all sword hearts.
Bring all the offerings to Lvdovico.
Get all collectibles.
Help Cleofás in his path of redemption.
Achieve the maximum value of health.
Buy all skills from the Mea Culpa shrines.
Achieve the maximum level of the Mea Culpa sword.
Achieve the maximum value of flasks.
Achieve the maximum value of rosary bead slots.
Achieve the maximum value of fervor.
Beat Quirce, Returned by the Flames.
Bring all the offerings to the Blessed Lord of Salty Shores.
Get all relics.
Buy all the items of the Candelaria shops.
Help the Pilgrim reach his final destination.
Hatch the Egg of Altasgracias.
Unlock the ending B.
Beat His Holiness Escribar.
Beat all types of enemies.
Discover all zones.
Beat Crisanta of the Anointed Blade.
Beat Melquíades, The Exhumed Archbishop.
Beat Exposito, Scion of Abjuration.
Execute 5 different enemies.
Beat Esdras, of the Anointed Legion.
Witness the last moments of Viridiana.
Beat the Tres Angustias.
Kill 666 enemies.
Visit the tomb of The Lady of the Tailed Gown.
Beat the Our Lady of the Charred Visage.
Beat Perpetua.
Beat Ten Piedad.
Beat the Warden of the Silent Sorrow.