What if you have #HitPoints AND #HitLocation?

Choose a target location, the more specific the greater the penalty.

Make your roll without the location penalty. If you hit, and your margin is high enough, you struck that location. The hit points are subtracted, and there is an additional effect for the location.

If your margin is less than the location penalty, then you still cost them hit points, and that might have a general penalty. Of course, reach 0 and you're out of commission.

#TTRPG