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