The Roll for the Galaxy expansion Rivalry consists of three expansions in one box.
First, it adds expansion content to the base game: 62 more game dice, a new die type, start factions, home worlds, and more than double the number of game tiles for the bag as in Ambition, the first expansion for Roll. This material is compatible with Ambition, but that expansion is not required to play Rivalry. If you are familiar with the dice from Ambition, then you can add this content and start playing immediately. (If not, you'll need to read about the new dice.)
Roll for the Galaxy: Rivalry also contains two optional game modules — the Deal Game and the Orb Game — which can be played separately or combined. These modules can also be combined with the goals in Roll for the Galaxy: Ambition.