The object of the game is to complete more of the five missions than your opponent. Points are scored for completed missions and lost for holding multiples of various cards. Component cards are used to complete missions, effects cards affect mission completion, galaxy cards allow drawing of advantage cards which allow you to take extra turns, move cards around, look at your opponent's hand, etc. You draw and play from a common deck with six cards in hand. The game is not collectible as all the necessary cards come in the pack. However, mine says New Millennium Deck, so there may have been other decks planned / produced. [Update 2011] I have a "Cosmic Journeys" deck aimed at astrophysics, so there are at least two decks for this game. [Update 2012] Additional deck "Missions to Planet Earth" also exists.