Each faction features a unique set of units, structures, and play style as well as its own segment of the single-player campaign.

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.

The game bases itself around "macro decisions over micro management" and features a qwert hotkey system for unit control and construction.

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 had returned to planet Earth in an attempt to seek peace and stability in a post-scarcity society guided by AI.

A signal is detected from the distant planet Ecosystem 9 in the outer Crux Arm, and the starship LSV Darwin, captained by Lucy Tak, is sent to investigate.

It is revealed that the Goo are attempting not to consume life, but rather to protect it from "the growing shroud of Silence" that is expanding across the galaxy — the same unknown force that destroyed the Beta civilization.

Hardcore Gamer gave the game a 4 out of 5, stating: "Grey Goo is a stand-out RTS that has found an expert way of blending old with new to create something familiar but fresh.