X-Piratez

X-Piratez is a total conversion mod designed for OpenXcom, a free open-source re-implementation of X-Com: Enemy Unknown (1994) and Terror From The Deep. There are major gameplay differences, as well as many additions to research, manufacture, base facilities, and so on. Piratez is designed for the veteran X-Com player seeking a much longer and challenging campaign.

From the "Our Fight" section under the "Bootypedia" (this game's version of UFOpedia): "Legends say once the Earth was ruled by humans, and there were no mutants at all. Even if such tall tales are true, it is all long gone. Nowadays the planet is just a distant periphery of the huge stellar Empire, ruled by the Star Gods. A poor backwater with corrupt government and brainwashed population, rife with crime - and opportunity. Mutants and outcasts like us are not loved by anyone, so we choose infamy over their sick and unjust order. They may call us pirates and criminals but it's better to die free than live for others."