You're absolutely right about Rifts being GMed by Gryphon...must be Algebra getting to me in my old age. ::feels reeeeealllllly stupid, crawls into a hole, and beats herself up, a la "Liar Liar"::

There's only one roleplaying game I know of in which the GM is supposed to be kicking the PC's butts, and that's "Paranoia". I can't imagine trying to work against your players in anything else, but more just being a god-like person who's making things happen, both good and bad. GM vs. PC seems like a really odd way to play, since the PC can't make things happen in the world, and the GM can.