Expansion for Base-game · Fan Expansion

The Unknown (fan expansion for Terraforming Mars)

This free to play fan-made expansion for Jacob Fryxelius' masterpiece Terraforming Mars is my attempt to combine my favorite game with my favorite sci-fi universe.

2–5 players120 minages 12

Save to my collection Log a play

About the game

What is The Unknown (fan expansion for Terraforming Mars)

This free to play fan-made expansion for Jacob Fryxelius' masterpiece Terraforming Mars is my attempt to combine my favorite game with my favorite sci-fi universe.

The core idea behind the expansion is to treat the planet — whether it’s Mars or LV-425 — as an unknown world waiting to be explored. You begin terraforming the surface with no idea what lies beneath, thanks to the hidden tile mechanics. This element makes colonization strategies harder to plan, as the bonuses from placing tiles are not always known in advance. However, this uncertainty can shift the dynamic — powerful bonuses can still be uncovered, and triggered events may impact your opponents. The new standard action “Dropship” lets you scout areas in advance, giving you a better overview… and maybe the edge you need to win. You’ll also get the chance to interact with iconic characters from the Alien universe — including Newt, Xenos and even the Xeno Queen herself. Each one comes with their own customizable event lists. You decide whether the planet is a nightmare hunting ground for Xenos, a paradise rich in resources — or something in between.

Best of all, there’s no need to buy additional game boards. You can customize your own map every game — it’s all up to you. Make the experience your own.

The new mechanics don’t increase the game’s complexity — instead, they introduce a sense of mystery and exploration, bringing a more immersive colonization experience to life. Ocean and Mons regions are still clearly marked, so all core placement rules from the base game and official expansions remain fully intact.

Specs