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