Here is the full list of all 14 Monsters Den Chronicles achievements.
Complete all in-game achievements
Pass wave 10 in Act IV
Play Act IV and pass wave 30 (above Beginner difficulty)
Take all store categories to the maximum level
Reach level ten with ten different characters
Win a battle against 3 or more enemies without taking damage
Complete Act V
Reach level ten with any character
Complete Act III
Complete Act II
Complete a campaign on Veteran difficulty
Complete Act I
Complete a campaign with the Hardcore penalty
Complete a campaign with a party of two