From Sierra Entertainment:
Homeworld: Cataclysm is the first official episode within the Homeworld universe, taking you back to the setting of Homeworld roughly 15 years after the events of the original game ended. Improving upon the Homeworld interface, Cataclysm presents new features such as waypoints and sensor-manager attack commands to add a new dimension to the revolutionary combat and game play pioneered in Homeworld. In the campaign, you begin Cataclysm commanding a sect or kiith that has been marginalized after your people's victorious return to their homeworld of Hiigara. Traveling into uncharted space to repel an attack against another kiith, your fleet happens upon an alien probe that harbors an ancient evil. As events unravel, you will need to survive the onslaught of an enemy with terrifying abilities you can't match, fight off opportunistic Turanic Raiders and deflect the firepower of Imperial loyalists bent on destroying you and reclaiming Hiigara.
I got the Homeworld Cataclysm demo, but when I tried playing it, it dropped out of the game during the story screen. I tried changing the video parameters and reinstalling it. I read on a forum that others had problems getting it to play on Windows XP. There is supposedly a patch 1.01 or something that can fix this. Well, it would be nice if the patch was included in the demo.