In the RP games I usually play, there's something called a "critical hit" which is exactly that - you lose a limb, or a lung is punctured, or some other really serious damage is done to your person. The thing is, what exactly is hit is left up to the imagination of the DM. In planeshift, it would have to be described in absolute terms, and there would have to be graphics for it.
There are a few problems though, perhaps you can think up solutions?
- How can Planeshift have blood and gore, yet still be accessible to young players?
- After losing a limb, how and how well will a player recover?