Here is the full list of all 18 And So It Was achievements.
Pick up 150 pickups.
Open 150 containers.
Complete the tutorial.
Reach the Castle.
Reach the Woods.
Reach the Mines.
Reach Snow Field.
Find all secrets.
Read all lore.
Make all unique deals.
Complete the Spellbook.
Finish the game.
Defeat 150 enemies.
Faint 50 times.
Beat the game 10 times.
Faint from using Hard Hit.
Faint after defeating the final Guardian.
Find the Christmas secret.