Lunacid

1. 
   Fledgling

   Reached Level 25
   51%
2. 
   Warrior

   Reached Level 50
   36%
3. 
   Knight of The Moon

   Reached Level 75
   24%
4. 
   Fetid Mire

   Reached the Sewer
   65%
5. 
   Came Back Haunted

   Reached the Catacombs
   53%
6. 
   Yosei Forest

   Reached the Forest
   53%
7. 
   Blood Lake

   Reached the Lake
   54%
8. 
   Hollow Castle

   Reached the Castle
   37%
9. 
   Demon Slayer

   Slew an Abyssal Demon in a lake
   36%
10. 
    Strange VHSSecret

    Steam withholds the description of a secret achievement.
    20%
11. 
    Forbidden Archives

    Reached the Grand Library
    42%
12. 
    LUNACID

    Woke the Old One, achieved the true end.
    20%
13. 
    BasiliskSecret

    Steam withholds the description of a secret achievement.
    20%
14. 
    Vampire PrinceSecret

    Steam withholds the description of a secret achievement.
    33%
15. 
    Ending ESecret

    Steam withholds the description of a secret achievement.
    8.4%
16. 
    Gates of TartarusSecret

    Steam withholds the description of a secret achievement.
    11%
17. 
    Complete Arsenal

    Obtained every weapon
    6.0%
18. 
    Moonlight Mage

    Obtained every spell
    9.1%
19. 
    A Moonlight SwordSecret

    Steam withholds the description of a secret achievement.
    22%
20. 
    Death RebornSecret

    Steam withholds the description of a secret achievement.
    11%
21. 
    Ending CDSecret

    Steam withholds the description of a secret achievement.
    11%
22. 
    The Unkillable CurseSecret

    Steam withholds the description of a secret achievement.
    21%
23. 
    Terminus Prison

    Reached the Prison
    30%
24. 
    Labyrinth of AshSecret

    Steam withholds the description of a secret achievement.
    22%
25. 
    Forlorn Arena

    Reached the Ruined Arena
    26%
26. 
    Master Alchemist

    Unlocked all of Etna's alchemy recipes
    7.5%

Names, descriptions and icons are the game’s own, as Steam publishes them; the share is how many owners have unlocked each, from Steam's global figures for 26 of them.