Grey Goo is a real-time strategy game developed by Petroglyph Games and published by Grey Box. The game was released in January 23, 2015 for Windows PC. The first campaign of the game takes place on a fictional planet known as Ecosystem 09, and the story centers around an ongoing conflict between three factions and their struggle for co-existence.
In Grey Goo players can choose one of three playable factions: the Humans, the Beta, or the Goo and use them to complete a single-player campaign or play in a competitive multiplayer mode versus other players. Each faction features a unique set of units, structures, and play style as well as its own segment of the single-player campaign. The Beta faction relies on speed, mobility, and power to dominate the battle through battle machines and specific units able to mount themselves on "hard-points" for defense. The human faction is well-rounded and highly based on reconfiguration of their base. They possess teleportation technology, able to reconfigure their sentinels and other structures and also transport their units to anywhere on the battlefield. The Goo faction features the game's namesake, self replicating nanobots that can move around the map consuming enemies and forming themselves into new units. Due to this, they only rely on pure strength and speed to destroy anything in their way. The game bases itself around "macro decisions over micro management" and will feature a qwert hotkey system for unit control and construction. Also, maps feature terrain obstructing vision similar to games such as Dota and League of Legends.
The story takes place 500 years after humans first ventured outside of the solar system.
The Beta (or Mora, as they call themselves), a once-spacefaring culture, has fled with the remainder of their civilization to the planet the game takes place on from an unknown threat they call "The Silent Ones". During a test firing of the wormhole they meant to use to return to the stars, they are attacked by enemies coming through the portal, or "Keyhole". These advanced drone units are first suspected to belong to The Silent Ones but are later revealed to be human in origin. As the conflict between the Beta settlers, led by Aran (Commander) Saruk, and the human forces intensifies, an explosion in orbit scatters wreckage all over their colony, from which the Goo emerge and attack both sides.
After a long history of war and exploration in space, during which no intelligent life was found, humans returned back to planet Earth in an attempt to seek peace and stability in a post-scarcity society guided by AI. A signal is detected coming from distant planet in the outer Crux Arm, designated Ecosystem Nine, and the starship LSV Darwin, captained by Lucy Tak is sent to investigate. Landing forces engage the Beta (which are named as such since their original planet was the "beta candidate" for intelligent life during previous radio telescope surveys, but subsequent investigation did not receive any more signals - likely a consequence of the Silent Ones' attack) and collect samples from the surface, including Goo, which promptly escapes and destroys the Darwin, reaching the Beta colony site in the re-entering wreckage. Despite the initial conflict, the Beta and the now-stranded humans agree to an alliance to destroy the Goo that threatens them, which is revealed to be the part of the artificially intelligent "Pathfinder" Von Neumann probes sent from Earth centuries prior to chart the galaxy in advance of the human expansion; the probes were believed to have been decommissioned when exploration was abandoned, but presumably the Goo on Nine somehow altered its own programming, becoming self-directing.
After sacrificing himself to destroy what was believed to be the last Goo on the planet, the robotic human commander Singleton's consciousness merges with the Goo. It is revealed that the Goo are not attempting to consume life, but rather protect it from "the growing Silence" - hinted to be the same unknown force that destroyed the Beta civilization, with all previous attacks simply being the Goo attempting to grow to facilitate this. With Singleton's assistance, the Goo fights back from the brink of defeat and carves a path to the Beta's last remaining Keyhole device in the hope of contacting and reuniting with the scattered Goo across the galaxy, to stand as one against the "Silence". Singleton attempts to negotiate with the Humans and Beta but the Goo is forced to destroy the opposing armies. Defeated, Saruk, Tak and others who were spared because of Singleton's belief that they will be pivotal in the battle to come, watch as countless Goo masses emerge from Keyholes across the planet.
In an after-credits scene it is hinted that the "growing silence" has discovered Ecosystem 9.