New element of gameplay, the Melange.
Can be found raw, but also in some potions and perma food : spice beer, spice cake, spice coffee...
Has no effect if taken very few.
If you take more, you become mildly addicted, it boost your HP regeneration by 10% but if the level of spice in your body reach zero, you will get 1+D6 penalty for each stats and must wait 2500 turns to loose addiction.
If you take even more, you become higly addicted. The regen boost goes to 20%, and you can sense monsters in your surrounding. Your eyes turn blue and if your level of spice reach 0, you get 1+(2)D5 penallty for each stat, and your speed goes down by 1. In 2500 turns you become middly addicted.
Wants more? You will become dependent. The game will always tells you if there it is a unique on the level. You gain controlled teleport and can map small area. Regen is up by 25% and max MP up by 10%. But if your spice level ever reach zero, you get 1+(3d4) less stats, -.1 speed, double miscast effect, randomly loose consciousness and die after 500 turns.
If you make an overdose, by eating to much spice, or getting caught in a spice blow, 50% chances of a bad mutation and get confused.
Sometime a portal appear in a level, announced by "it smells cinnamon". It brings you to a huge source of melange in a desert, but watch out the pack of Orcs armed with crisknive (a +9 +9 dagger of protection that disintegrate when his wielder die) will defend their rocks, and the mighty Sandworm watch his sand.
P.S. Yes I'm reading Dune again...