GURPS Tempest, a Post-Apocalyptic Science-Fantasy Worldbuilding Project ~inspired~ by Palladium Rifts* - Part One
*Disclaimer: And I emphasize the point "Inspired" as I don't want to get sued. This is an independent rpg worldbuilding project that isn't intended to be a direct 1-to-1 adaptation of Palladium's Rifts setting. 
Reposting from this thread ( https://forums.sjgames.com/showthread.php?t=206320 ) here because I want there to be an independent thread for this on my blog.
So, a while ago, over on rpg.net, I started a bit of a thought experiment after going through my collection of Palladium rpg pdfs: Rather than just converting Rifts, I wanted to try rebuilding the setting from first Principles using only GURPS products.
This is because I feel as if GURPS, a rule-set designed to be flexible enough to run any kind of setting, would be ideal for what is ultimately the ultimate Science-Fantasy Kitchen Sink setting. And because I've always had some issues with certain elements within the setting and the ruleset, I figure starting from scratch with GURPS will let me fix those issues.
So, for those unfamiliar with Rifts, here's the core premise: Planet Earth is ravaged around the early 21st Century when a nuclear war sets of a magical cataclysm that wipes civilization off the face of the Earth, brings magic back to the world in a big way, and tears open massive dimensional portals that lead to magical creatures and races, from small pixies to massive dragons, and from elves and dwarves to demons and ancient gods, suddenly all manifesting on Earth, alongside more mundane alien life-forms.
Centuries later, Humanity is slowly climbing back up from the brink of extinction, with some factions embracing magic and supernatural powers, while others focus on rediscovering lost technologies. And while the world is now full of undead monsters, demons, dragons and alien invaders, one of the big threats of North America after the end is a fascist, xenophobic human empire slowly expanding its borders.
This is a world where player characters can range from vagabonds and wandering mercenaries to mages, powerful psionics and actual dragons. Often in the same party.
Now, adapting this core premise to GURPS rules, I had the idea of the inciting event being a nuclear war that triggers a mix of Hellstorms (from Technomancer) and Banestorms (from Banestorm/Infinite Worlds), where the nuclear explosions turn into massive manaclysm storm events that bring magic and alien beings across the world, causing societal collapse.
For a global Tech Level, I'm thinking an average of 8-9 depending on the region, with some areas having lower tech (but compensating with magic and other powers) and some areas having higher tech (but limited production capacity.)
This simulates one of Rift's core concepts, being that humanity endures the rise of magic and monsters in the wilderness by using advanced tech like battlesuits, beam weapons and mecha.
In terms of magic and other powers, I'm definitely thinking of allowing a wide range of power options: classic Spell Magic, Ritual Path Magic, Psionics, Chi, Sorcery, Super Powers, etc. The overall global Mana Level would be Normal, with a Ley Line network, where Manastorms (serving as both persistant Banestorms and minor Hellstorms) would act as Mana sources, with higher levels of Mana along the lines.
This would be a cinematic setting, so GURPS Action with a mix of Monster Hunter and After the End would be the core around which the setting would be built.
So, to sum things up in this first post, I'm thinking of building a Post-Apocalypse cinematic action Science-Fantasy world inspired by Rifts, with an average TL of 8-9, a Normal Mana level, a wide range of character options.
This is just an opening Post, I plan on expanding this concept further once I get my notes together.