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