Although the information about the game was released last week, the official press release announcing the game was given today. Here's a quote: <blockquote>"PlanetSide is growing everyday and fans are constantly asking for more," said Michael Lustenberger, director of product marketing, Sony Online Entertainment. "With this first expansion, the dynamic of the game will evolve as all three PlanetSide empires battle to secure powerful new technology in order to dominate the planet Auraxis both on the surface and underground."
PlanetSide: Core Combat adds a new style of gameplay to PlanetSide with head-to-head urban warfare, testing players' skills as they react quickly to enemy troops in high-adrenaline fire-fights in subterranean alien complexes. With six new underground war zones, additional weapons, vehicles, and enhanced empire bonuses, Core Combat creates a new dimension for players to master in PlanetSide's all-hours-of-the-day online conflict.</UL>You can find the full press release
here.