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