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