You can't go wrong with this Cosmic encounter expansion! It adds even more replayability to a game that is already almost endless in its' possibilities. If you play with this expansion, I would recommend replacing the aliens in the original game for the first few playthroughs so you get the most out of this experience, and then later on eventually mixing everything together. The chaotic nature of this game is actually what makes it so exciting; you never know who is going to win, even up to the last turn.