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