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