From Dungeons of Dredmor Wiki

Realm of the Diggle Gods is the first DLC expansion for Dungeons of Dredmor and can be purchased on Steam for $2.99USD. This expansion was release on December 14, 2011.

[edit] New Features

• Six new skill trees: Big Game Hunter, Demonologist, Emomancy, Killer Vegan, Piracy, and Werediggle.
• One Hundred New Items (about)
• Five new dungeon levels
• Mysterious portals now randomly appear
• Scriptable rooms
• 12 new monster types
• Polymorphing
• Rune Rooms