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