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