Games like UFO Online: Invasion

In Star Trek Online, the Star Trek universe appears for the first time on a truly massive scale. Players take the captain's chair as they command their own starship and crew. Explore strange new worlds, seek out new life and new civilizations, and boldly go where no one has gone before.

Wage a global war of resistance against an alien invasion. Command turn-based tactical battles, build a network of covert bases, directly control your fighter wings, and achieve strategic victory in a simulation of asymmetric warfare against a technologically superior foe.

Anarchy Online – the first ever science fiction MMO – is now on Steam! Compete and cooperate with thousands of players simultaneously on a vast, alien world. Join humanity nearly 30,000 years in the future in a world of perpetual conflict and scientific marvel.

Fallen Earth Classic is a free-to-play massively multiplayer online role-playing game developed by Reloaded Productions and operated by Little Orbit. The game takes place in a post-apocalyptic wasteland located around the American Grand Canyon.

Welcome to Affected Zone Tactics, a tactical online game with cooperative turn-based PvP combats. Travel through the Tesla portal to a dangerous parallel world, lead the squad of reckless mercenaries, and outrage mighty corporations and cliques.

From the developers of Warhammer 40,000: Gladius, ZEPHON is a post-apocalyptic 4X strategy game built on Proxy’s unique tactical combat system. Guide survivors through a turbulent future, navigating unexpected disasters, eldritch horror and cyberpunk monstrosities. What will you do to survive?

XCOM 2 is the sequel to XCOM: Enemy Unknown, the 2012 award-winning strategy game of the year. Earth has changed and is now under alien rule. Facing impossible odds you must rebuild XCOM, and ignite a global resistance to reclaim our world and save humanity.

Ascent is a PVE sandbox space MMO with 270 BILLION star systems and an emphasis on strong Sci Fi. It encourages Exploration, Colonization, Research, Asteroid mining, Farming, Trading, and Combat. Outside the tutorial sector, everything in-game has been built by players.

Xenonauts is a strategy game in which you control a multi-national military organisation defending a Cold War-era Earth from alien invasion, using small squads of persistent soldiers to eliminate the extraterrestrials and recover their technology in turn-based ground combat.

Operation: New Earth is an intense sci-fi multiplayer strategy game in which you must command an advanced military facility to defend Earth from a hostile alien invasion. Create an alliance, gather resources, and unlock advanced technology to level up your stronghold!

Anomaly Zone is an open world MMORPG and a post-apocalyptic shooter. Be a scientist, a soldier, a hunter or an engineer. Explore anomalous territories, search for artifacts, fight mutants and other players. Participate in mass PvP and PvE battles. The Zone is waiting!

You are in control of X-COM: an organization formed by the world's governments to fight the ever-increasing alien menace.

Starfall Online is a real-time multiplayer strategy mixed with wargame. Three rival factions — Deprived, Vanguard and Eclipse rule the world, and you are to become the part of the confrontation between them. Gather your own fleet and embark on a journey through the Galaxy!

Tactical story-driven online multiplayer game combining the turn-based combat of X-COM with a deep, well-grounded sci-fi setting. Experience intense tactical online multiplayer action and explore a deep plot and unique storyline built on both single-player and multiplayer missions.

UFO: Aftermath is a 3D isometric, tactical strategy game with a rich and compelling sci fi story.

There's something evil in the city tonight... Earth has been ravaged by human excess, petty conflict and alien invasion. The world's population has been herded into huge cities, the first of which was Mega Primus. 2084: A Utopia shattered, social collapse and civil unrest reigns in Mega Primus. Fiendish aliens terrorize the city.

Fly through Subspace, build your own ship, and engage in epic battles. Mine asteroids and research new technologies. Uncover the origins of the alien homeworld by solving weekly events in this Co-op PvE MMO.

The XCOM: Enemy Unknown - Slingshot Pack is Now Available!