Complex sentence: It is based on the writings of J. R. R. Tolkien, in which the objective is to face the 100 levels of the title dungeon and amass enough power and equipment to ultimately defeat Morgoth.
Split into simpler sentences: It is based on the writings of J. R. R. Tolkien. The adventurer is presented with 100 levels of the title dungeon, in which he or she seeks to amass enough power and equipment to ultimately defeat Morgoth.