I like the idea of radiation.. If your in the radiation zone (Could be quite big), your health would go down slowly.. Maybe a radiation meter..?
I have not a scripter (At the time being.. I want to learn, but I have lots to do these days..), I can edit bits in them... So, basicly, I have no idea if this is possible, and if it is, how you would do it (Maybe a Hint thing, with a number of percetage of radation in the area your in..)
Just going to test the script just now...
- Ben