More Difficulty Levels by Iizvullok

Adds several new difficulty levels to the game. After the vanilla difficulties peaceful, easy, normal and hard, there are now (in order) expert, nightmare, fiendish, cataclysmic, pandemonium, unutterable and insurmountable. Don't go straight to the highest difficulty and then complain that its impossible. Because on the higher difficulty levels, the game beats you. This is not a joke.