Here is the full list of all 17 Dungeon Hearts achievements.
Achieve an attack multiplier of x7 or more in a single attack.
Complete the tutorial.
Unlock 10 Enemies in the Bestiary.
Unlock 20 Enemies in the Bestiary.
Unlock 40 Enemies in the Bestiary.
Reach battle 15.
Reach battle 7.
Defeat The Dark One.
Use all four Heroes in a single attack.
Reach Level 20 with any Hero.
Reach Level 60 with any Hero.
Use all four Hero's final Skill in the same battle.
Finish the game in 40 minutes or less.
Finish the game without any Hero getting knocked out.
Finish the game without using any Skills.
Finish the game with at least one Level 1 Hero.
Defeat The Dark One on Hard difficulty.