By tomorrow eager players will finally be playing a highly anticipated science-fiction strategy sequel; speaking, of course, of Natural Selection 2, the RTS/FPS hybrid from Unknown Worlds. Tonight a playable alpha will be released via Steam for those who have preordered either the standard or special editions of the game, which can be done through the Natural Selection 2 Website. Time is running out, however, as after today the special edition will no longer be offered, the price will go up on the standard edition, and preorders will no longer carry an invitation to play the alpha.