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