The single biggest complaint about Rifts is MDC. Originally introduced in Robotech to give different scales for mecha from humans it actually worked fairly well. One MDC=100 SDC (hit points). More importantly, while it scales down (1 MDC to an SDC structure/person is recorded as 100 SDC) it doesn’t scale up (doing 100 SDC to an MDC creature does nothing).
However, when transplanted to Rifts and applied to creatures as well as objects it started to break down. Specifically, if MDC weapons are in use and you don’t have MDC armor you are 1 hit (maybe 2 if you don’t have excess blow through armor) from death. There are MDC hand guns in Rifts while some tanks have SDC guns so an infantry man in MDC armor with one of this pistols can walk up to a talk and waste it without risk.
The general solution is to reduce MDC:SDC ratios (20:1 and 10:1 are popular) and allow SDC to do divide by ratio and round down MDC damage. A much better solution, in my view, was presented by Jim Stoner a decade ago. My S&W RDR system draws heavily on it.
The key idea is hit points/armor and damage ratings have both a number (25 hp, d6 damage) and a scale (normal, superhuman, supernatural). When the scale of the target and the attack are the same it’s just a normal game. It is important to remember armor can upgrade your defenses. If you have modern armor treat your defenses as superhuman when figuring effects of hits for example. When they are different the following chart gives the changes to the effect.
|Attack Type||Defense Type|
|Normal||Glancing||No Damage||No Damage||No Damage|
|Hit||Full Damage||Half Damage (round down)||Quarter Damage (round down)|
|Superhuman||Glancing||Half Damage||No Damage||No Damage|
|Hit||Double Damage||Full Damage||Half Damage (round down)|
|Supernatural||Glancing||Full Damage||Half Damage (round down)||No Damage|
|Hit||Quadrupled Damage||Double Damage||Full Damage|
Critical Hits:A roll of a natural 20 is a possible critical hit. Roll the attack again and if it hits treat it as one scale higher. This is an open ended roll up to a Critical Supernatural hit which does double the supernatural damage.
If an attack is insured at least a glance a roll of 1 will do no damage regardless of damage class difference.
What does what class of damage and provides what class of effect?
Hand to hand attacks by normal humans and similar monsters plus most pre-modern weapons do normal damage. Armor from the same period provides normal defense. Most creatures and structures have normal hit points.
Modern weapons (post 1920ish) do superhuman and modern armor is superhuman in defense. Modern harden structures and armored equipment have superhuman hit points. Some medium level magic and supernatural creatures (troll, ogres, giants) might do superhuman damage and have superhuman hit points.
Highly magical creatures such as dragons and demons, very powerful magic spells, and Clarke’s Third Law level technology do supernatural damage. The creatures and equipment at this level have supernatural defenses.
Note on Magic Weapons/Armor:My general rule for magic weapons/armor will be they do the class they are in unless otherwise noted. There is no reason a sword +1 or plate +1 can’t be rated superhuman. My one exception would be shields. I would not let shields alone upgrade defenses.