Here is the full list of all 13 DeathSpank: Thongs of Virtue achievements.
Kill 3000 Enemies
Kill the Taking Tree
Watch Both Game Endings
Discover all 44 Teleporting Outhouses
Kill Santa Claus
Reach Level 20
Go Sailing in a Pirate Ship
Kill Wortten
Learn to Speak Japanese
Get an Engineering Degree
See all 20 of Madame Primp's Outfits
Kill the Evil Nun
Convince an Orque Guard you are an Orque