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