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