Dead Gods Rising & Diesel Punk World at War
Massive Damage Threshold (MDT) is a rule that will be in play, though it may not always be closely watched. MDT = CON score + Character level. If you take more than your MDT score from a single attack you must succeed a DC 15 Fort save. This DC increase by 2 for every 10 points beyond your MDT. Failure means that you loose ½ your max hit points, or get dropped to -1, whichever is lower. In addition you must check to see if any cybernetics you have were damaged.
When taking non-lethal damage, if the damage exceeds your MDT you must make a Fort save as normal. If you succeed you are dazed for 1 round. Failure means you are knocked unconscious for 1d4+1 rounds.