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