science fantasy

Highest Ground is a free science fantasy board game. The author writes:

The Highest Ground is a game that imagines a world with a very long period variable climate. Where an alien species has, approximately every 800 Earth years, collected a band of warriors from the most advanced warrior state on Earth at the time, and transported them to this planet. There they are to achieve dominance over the local population, grow a crop for the aliens, and, in the ensuing climactic holocaust, be almost wiped out and, therefore, not become a threat to the aliens.

At the time depicted by the game the have just bagged a new group of Earthlings and taken them to the planet. This group
is from 1979 and is a bunch of mercenaries on the losing side of an African civil war. They have been grabbed from a
soon to be terminally untenable position. They have been taken to the planet where the society that has grown up
around the survivors of previous recruiting drives consists of several warring states peopled by Medieval feudal kingdoms and knights, Roman Legions, pony riding barbarians and Egyptian pharaohs. The game finds the few mercenaries, having allied themselves with the European kingdoms, at war with the local Roman Empire.