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