GOG is giving away Sigma Theory: a strategy game set on an XCOM-like hologram of Earth, where the world's superpowers send their agents and drones to compete for technological advancement. The game is a turn-based spy game and draws inspiration from Tropico, Almelo, Civilization, Plague Inc. and the board game Pandemic.

Sigma Theory was designed by Mi-Clos Studio, creators of the Out There series. The agents are chosen from a pool of 50 people, each with a backstory and personality traits that dictate what actions to take and influence how good or bad they are when being chased through the streets or attempting to hijack classified documents.

There is also diplomacy and research, and a technology tree that includes hypnotic indoctrination, combat robots, accurate stock market predictions, alternative energy sources, and immortality. The "Sigma Theory" of the title is the scientific breakthrough that makes all of this possible and puts the world on the fast track to Singularity.

As the head of a country's sigma department, what you do with each breakthrough will affect the doomsday countdown, depending on whether you share it with the world, sell it to private companies, or save it for your own government. So, I say, let's not call ourselves "Lucky Lorenzo" and sell everything to a man who works for the cartels.

Sigma Theory is available for download on GOG: It will be available for free on GOG until Monday, June 19 at 6 a.m. PST; GOG is also currently running a summer sale, with "Tangle Tower" at 80% off, "Outward: Tangle Tower at 80% off, Outward: Definitive Edition is 75% off, Last Call BBS is 50% off, and Unpacking is 40% off.