Rifts was made during a time where AD&D was seen as the gold staple of RPGs, and as such is a hack of AD&D with 2-5 more dice rolls for any combat turn, and 100 more skills. Then there are loads of subsystems for magic, chi, psionics, biomancy, and so on that all work just differently enough that you'll want to read up on them before they come up in game, vastly differing tech levels with various levels of (in)compatibility everywhere.
The setting itself had shit like wild west bandits firing revolvers that become magical simply due to the sheer grit of the bandit, who rides a dinosaur that may or may not actually be a robotic drug mule disguised as a dinosaur. Giant tyranid swarms devouring all life in what was once the south western united states and mexico. A man who took his inspiration on how to lead people literally from watching History channel documentaries on Adolf Hitler, and now runs a massive military faction that is humans only and believes in purging the mutants and the witches (except for those that can be easily controlled by their superior pure human brethren). A federation of magic users, both good and supremely evil ones, with access to all sorts of crazy techno-wizardry in addition to their powerful magics, and a few godlings among them
And that's only a brief glimpse of what's happening in north america, leaving out the return of merlin in england, or the huge leaps in technology in germany, the gargoyle armies, the warlords of russia, the horsemen of the apocalypse in africa, the demon kings returning to asia, and FUCK SOUTH AMERICA.
Let alone the shit going on in the galaxy at large or the other two major galaxies.
But that is the one strength Rifts had, you could play more or less any concept or idea within it, and there would be a place for it somewhere in the setting, likely with stats written for it as well.
Owen Sanchez
Bump because the mere idea of this makes me harder than MDC armor