Take the role of an adventurer that tries their fate in the dark dungeons (and probably dies horribly). Fight monsters, grab loot, hoard potions, and level up!
Quest for the Yithidian orb at the darkest depths of the dungeon and attempt to bring it back to the surface - getting to it may be the easy part.
Levels are randomly generated in each playthrough so you'll never know quite what's around the corner.
Delver is in an unfinished beta...