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