From Stronghold:
As the mega corporations are getting ready to start the terraforming process, you now have the chance to make those early choices that will come to define your corporation and set the course for the future history of Mars – this is the prelude to your greatest endeavors!
In Terraforming Mars: Prelude, you get to choose from Prelude cards that jumpstart the terraforming process, or boost your corporation engine. There are also 5 new corporations, and 7 project cards that thematically fit the early stages of terraforming.
Prelude is an expansion to Terraforming Mars, and can be combined with any other Terraforming Mars expansion or variant.
The new expansion was designed by Terraforming Mars’ creator, Jacob Fryxelius, and includes 47 cards. As an expansion, it requires a copy of the base game to play, and is fully compatible with all other expansions, including Venus Next.
