I noticed that uranium boulders/sticks/etc. have been added. How about adding radiation poisoning
to go with them?
For simplicity's sake the damage could only apply within 1 square ('touching'), but having damage ticks fall off as you're farther away could be possible if someone wants to do the maths. There should be thresholds at which damage increases, defined by how much total units of Uranium material are in a square; at high values you suffer burns while also taking Poison damage. Also take a 10x multiplier to your torso if said material is in the player's inventory, or to a limb if an item made of Uranium is wielded or worn. Throw in random Uranium golems to emphasize the new mechanic.
If you want to get really nasty
* Add a threshold for criticality
. Stack waaay too much Uranium in a square and all of the sudden it will start glowing blue
with a unique message, plus taking a massive poison dose.
* Add an "Is_radioactive" tag for metallic items and have them inflict a fixed damage-per-turn based on the total threshold + turns they've been exposed. Don't pick up that +5 thunder hammer that's been lying next to the Uranium boulder...kick it away and leave it for a while.
* Have healers refuse to treat severely irradiated players.
Here's a few more ideas:
* A novel use for gas immunity in the form of a small dungeon with an unbreathable environment. Mines and wands of fireball can still go boom but nothing can actually burn. The player also starts suffocating (head damage?) unless they are polymorphed into a creature that doesn't need to breathe, have an amulet of magic breathing or are otherwise gas immune. The danger itself should be subtle. Alert players might notice that no living creatures are spawning (b/c they can't survive). Maybe throw in a mystic dark frog for a chance to suddenly rip away the amulet they were relying on!
* Trap rooms. Similar to Chest Rooms
except when the player steps inside the doors lock and various forms of unbreakable traps (terrain icons) pop up to make your life miserable?
* Enable death-by-stupidity on the Attnam torture devices. Sitting on the wooden horse = guaranteed 1 HP damage to torso, closing the iron maiden while 'inside' it = severe piercing damage to multiple random body parts.
** In the same vein, a chance of falling into a well and drowning if you "sit" on it and fail some kind of stat check to climb out.
* "Flatulent" status, where you randomly emit a cloud of gas, to drinking pea soup. This should be an invisible status and possibly count as a hostile action to neutral NPC's.
* "Mute" status, preventing you from chatting to anyone but healers until cured.
* A sidequest to help Petrus' unhappy wife escape from Attnam without alerting the guards. Different text screens and rewards for getting her out quietly vs. violently.
* Dipping a container of water into
a container of acid
should cause a minor (1x1 tile) explosion and getting acid splattered on you.