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