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