Start Here: System Versus World
This project is the reusable System layer for Palladium-based Craft Worlds. The first design decision in every extension is therefore a boundary decision: does this belong to the shared engine, or does it belong to one game/edition World?
What belongs in the System
Keep concepts here when they are reusable across multiple Palladium RPGs: core file types, schemas, layouts, reference patterns, configurable profiles, generic GM behavior, common vocabulary, and engine capabilities such as attributes, percentile skills, class references, combat modifiers, durability pools, resources, and advancement state.
The System should make a mechanic possible without silently choosing one title's implementation. For example, the System can know that an Environment may be S.D.C.-focused or Mega-Damage-focused. It should not decree one Rifts conversion rule as universal. It can represent attacks per melee; it should not force every game to use the same untrained baseline.
What belongs in a World
The World supplies exact game and edition content: source precedence, attribute generation, bonus tables, saving-throw targets, class lists, R.C.C.s, species, skill catalogs, Hand-to-Hand progressions, Weapon Proficiencies, magic, psionics, super abilities, equipment, monsters, technology, setting lore, locations, factions, characters, and any title-specific exceptions.
If the same concept exists in several Palladium games but its numbers differ, the System owns the schema and the World owns the values. If the concept only exists in one game line, it usually belongs entirely in that World or in a reusable package intended for that line.
The generic templates
Use @Missing file as the model for a World Rules Profile, @Missing file for attribute rules, and @Missing file for character creation. They are intentionally incomplete. Their blank numeric arrays are not missing System data; they are extension points where a World inserts its own rules.
The same is true of @Missing file and @Missing file. They demonstrate two broad environment shapes without defining one game's damage interactions.
Do not "fix" deliberate blanks
A common failure mode is seeing an empty table in the generic System and filling it with the numbers from the first book at hand. Do not do that. Ask whether the number is truly common to the Palladium family. If you cannot support that claim across the intended games, leave the System configurable and place the value in the World.
The System is successful when a builder can choose it as a starting point for Rifts, Palladium Fantasy, Heroes Unlimited, Nightbane, Beyond the Supernatural, After the Bomb, Dead Reign, Splicers, or another compatible title without first deleting assumptions from an unrelated game.