I just wrote up a very rough script on how to handle elemental damage.
This defines two elements, ice and fire. If you hit an elemental enemy with the same element weapon, they only take half damage. The example quest gives you a fire sword and an ice sword.
You define the element of a weapon by setting it's damage. The actual damage starts at the ten's place, and the element is the one's place. So if you set a sword to do 61 damage, it will do 6 fire damage. If you set it to do 42 damage, it will do 4 ice damage.
Enemies are assigned an element at Misc Attribute 11, with the same element numbers. This conflicts with Ghosted enemies, but if you're using them you can probably assign an element in the actual enemy script easily enough.
This works by giving every enemy a lot of extra hp when they first appear, and then checking their health every frame to see what kind of 'hit' they took last frame and rearranging their health accordingly. Once they pass below the extra amount of hp they were given, they are killed off.
This could probably be very easily modified to create weapons that do other weird effects, not just varying amounts of damage.
Edited by grayswandir, 10 August 2013 - 03:59 AM.