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