Out of the ashes of war, a tentative truce emerges between the Humans, Beta and the Goo—but peace doesn’t last long. Ecosystem Nine finds itself thrust into turmoil once again with the arrival of a destructive, alien life form known as the Shroud.

Grey Goo is a real-time strategy (RTS) game that combines classic strategy mechanics and a balanced combat system with an emphasis on large-scale decision-making. It puts you at the center of a tactical struggle for survival—and ultimately, control of Ecosystem 9.

Take on the single-player campaign to command three factions: the Humans, masters of defensive architecture; the Beta, a proud, versatile alien race; and the Goo, an enigmatic, highly mobile life form. Or compete with any of the four multiplayer factions—including the disruptive, unpredictable Shroud.


  • Fight—or play as—the Shroud, a brand-new, multiplayer faction.
  • Command new units: the Humans’ Valiant, the Beta’s Squall and the Goo’s Siphon.
  • Explore an additional story arc with “Grey Goo: Emergence,” and discover the Goo’s true intentions.
  • Take on the Shroud in Mission 16, “Herald of Silence.”
  • Sharpen your battlefield tactics in the single-player campaign, or join the fray on Steam.
  • Join the fray on Steam and find opponents through skill-based matchmaking.
  • Change the rules of the battlefield with unit-altering tech upgrades.
  • Deliver devastating blows by constructing game-ending Epic units.
  • Take the battle offline via Local Area Network play.
  • Enhance your competitive edge with Replay Mode and Observer Mode.
  • Use the Map Editor to create your own battlefields and share them with the community via Steam Workshop.