Cornsnake's already spent 300 hours on the demo alone.
I've been trying out everything just to see how I want to build my character. The replay value is actually pretty good because most of the loot is randomized, you'll get something different every time. The number of enemies and the type also changes in a lot of encounters.
I'll have to wait until friday before I can get the game. I'm thinking of starting on Hard because I keep hearing how easy the game is, and there is an option to switch back to normal if needed.