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