Massive, randomized world to explore, Deep history and mechanics to dive into, Multiple playstyles
Takes a long time to know what you're doing, Finding somewhere specific can be obtuse, Tutorial only explains the most basic of basics
Caves of Qud is a game that will reward you more and more for putting in the time and effort to learn about it. Even just from scratching the surface, however, I am absolutely entranced by the worlds the game can create