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.
Get 100% of the game.
Get all rosary beads.
Provoke the meeting between Redento and Cleofás.
Save all Kissers of Wounds.
Witness the last moments of Viridiana.
Unlock the ending A.
Beat all the arena challenges.
Get all sword hearts.
Talk with all the corpses.
Achieve the maximum value of rosary bead slots.
Get all collectibles.
Get all prayers.
Release all cherubs.
Unlock the ending B.
Beat His Holiness Escribar.
Achieve the maximum value of flasks.
Visit the tomb of The Lady of the Tailed Gown.
Help Cleofás in his path of redemption.
Use the Righteous Riposte 5 times.
Get all relics.
Bring all the offerings to the Blessed Lord of Salty Shores.
Achieve the maximum value of fervor.
Buy all skills from the Mea Culpa shrines.
Help the Pilgrim reach his final destination.
Beat Crisanta of the Anointed Blade.
Discover all zones.
Beat all types of enemies.
Bring all the offerings to Lvdovico.
Achieve the maximum level of the Mea Culpa sword.
Achieve the maximum value of health.
Beat Quirce, Returned by the Flames.
Buy all the items of the Candelaria shops.
Beat Exposito, Scion of Abjuration.
Hatch the Egg of Altasgracias.
Beat Melquíades, The Exhumed Archbishop.
Kill 666 enemies.
Cross the Bridge door in less than 3 hours.
Beat Esdras, of the Anointed Legion.
Beat the Our Lady of the Charred Visage.
Beat the Tres Angustias.
Beat Perpetua.
Beat Ten Piedad.
Execute 5 different enemies.
Beat the Warden of the Silent Sorrow.