Compared to the first edition of Descent: Journeys in the Dark, this game features:

Simpler rules for determining line of sight
Faster setup of each encounter
Defense dice to mitigate the tendency to "math out" attacks
Shorter quests with plenty of natural stopping points
Cards that list necessary statistics, conditions, and effects
A new mechanism for controlling the overlord powers
Enhanced hero selection and creation process
Experience system to allow for hero growth and development
Out-of-the-box campaign system