The UnderGarden Achievements
Full list of all 15 The UnderGarden achievements worth 250 gamerscore. It takes around 8-10 hours to unlock all of the achievements in the base game.
The base game contains 12 achievements worth 200 Gamerscore, and there is 1 DLC pack containing 3 achievements worth 50 Gamerscore.
This DLC has been removed from the Microsoft Store and is no longer available for purchase.