Here is the full list of all 15 Heroic Dungeon achievements.
Complete 25 bonus levels
Kill 100 enemies
Find 25 hearts
Upgarde 3 items
Kill 10 enemies
Destroy 500 monster heads
Complete 1 dungeon
Complete 10 dungeons
Complete 5 bonus levels
Find 25 swords
Find 25 chests
Kill 1000 enemies
Destroy 5000 monster heads
Destroy 50000 monster heads
Complete 100 dungeons