Here is the full list of all 13 Dungeons of Sundaria achievements.
Complete The Crypt of Horrors on Normal
Obtain all Trophies
Complete The Dark Hollow on Normal
Complete The Grasslands on Normal
Complete Lair of the Ceranids on Normal
Complete The Crypt of Horrors on Hard
Complete The Dark Hollow on Hard
Complete The Grasslands on Hard
Complete Lair of the Ceranids on Hard
Complete The Crypt of Horrors on Nightmare
Complete The Dark Hollow on Nightmare
Complete The Grasslands on Nightmare
Complete Lair of the Ceranids on Nightmare