Staged bullet damage?

Here is something that might help you in a good direction. Note "center" can mean several things, pivot, center mass, center as the character is bisected. This code uses the pivot point. Because the pivot is (likely) inside the mesh, it will never score the maximum points.

 #pragma strict
 var maxDist = 1.0;
 var minPoints = 10.0;
 var maxPoints = 80.0;
 
 function OnColliderEnter(col : Collision) {
 
    if (col.collider.tag == "Bullet") {
         var dist = (transform.position - col.contacts[0].point).magnitude;
         var points = (maxDist - dist)/maxDist * maxPoints;
         points = Mathf.Clamp(points, minPoints, maxPoints);
     }
 }