"The full game will be free along with premium content that can be purchased in-game," Long said. "Blacklight will feature a large number of improvements based on the player feedback we've gotten. And we hope going free-to-play will close that loop so we can respond even faster to player preferences." And hopefully give Zombie more resources (read: money) with which to implement those responses, no doubt.
The new game will use Unreal Engine 3, but won't use any assets from its predecessor. New weapons, new levels, and new "mech" vehicles will be featured -- the latter of which can be seen in the single released screenshot, above. Since it looks totally awesome, we're guessing that's going to be a microtransaction-based item.