Here is the full list of all 13 A Healer Only Lives Twice achievements.
Game over
Enter Tier 3 (MAIN Mode or EX MAIN Mode)
Learn all skills
Cure Petrification or Poison by using items or skills
Attack three enemies at one time by using Courage skill
Defeat Golem
Defeat Troll Thug
Defeat Minotaur
Defeat Gryphon
Unlock all upgrades
Complete MAIN Mode or EX MAIN Mode
Complete TRIAL Mode
Complete EX MAIN Mode