The UFO 2: Extraterrestrials story takes place on Earth, before the events that occurred in the original UFO:ET.  The game actually takes place just before the events leading up to the human colonization of the planet Esperanza.

Earth is divided into 9 super states:   North American Brotherhood, European Union,  Russian Federation,  Asian Syndicate, Arabian League , African Coalition,  ALBA - the South American Alliance,  Australian Commonwealth,  and Free Territory of Antarctica. All the super states support the Counter Alien Forces organization.

The development studio Chaos Concept has decided to spend more time improving the design of the global gameplay as well as the tactical combat.  Some of the extra development time will be devoted to adding new features based on feedback by the fans. 

Some of the new features include:

• Alien mobile fortresses which the player must battle on both the globe and in tactical combat.
• New player-controlled aircraft, including several types of helicopters.  Different aircraft will have different combat capabilities forcing the player to use the right craft for the right job.
• More varied alien abilities in tactical combat to keep the players on their toes.  For example, the Magetra have the unique ability to consume dead aliens and humans to heal and energize themselves during combat.
• More varied tactical combat mission types.

There are 2 main styles of game play in UFO2ET: Geoscape and Tactical Missions.

Geoscape enables you to survey alien activities on the planet's surface and in the atmosphere. Through the Geoscape interface you will be able to dispatch fighters to intercept alien vessels and you will be able to directly control your craft in real-time combat. With your missile defenses, aircraft, and aircraft carriers you will be fending off swarms of alien vessels. The Geoscape interface allows you to design and build new bases. In these bases, aircraft may be built and equipped with the advanced missiles, cannons, armor, and shield reinforcements needed to combat the UFOs menacing the planet. Your aircraft carriers may be equipped with a variety of defenses, though your fighter aircraft will always be considered their main and most powerful weapon.  As commander, you will hire scientists and engineers to design and build new tools to aid you in your struggle.  You will also hire, train, and equip an elite squad of soldiers and send them to investigate UFO crash sites and alien activities all over the planet.  You will be able to equip your soldiers with various items to help them in their mission, including guns, rockets, grenades, lasers and other advanced weapons, armor, flying devices, medkits, and many other items.

The Tactical Mission is an essential part of the game. Somewhere in the typical UFO investigation Mission is a downed UFO full of aliens armed with powerful weapons. Their aim is to abduct, terrorize, and invade. Alien soldiers are highly trained, and thus accurate, fast, and difficult to kill. Your troops must locate and combat these aliens face to face.

UFO2: Extraterrestrials - Shadows over Earth

• A fully 3D game combining real-time global strategy & air combat with turn-based tactical missions
• A turn-based “I-Go-You-Go“ tactical squad-based game system
• Interactive environments with destructible terrain.
• A large number of technologies, weapons, and combat units to develop
• A large number of aliens to interrogate
• Strong RPG elements where soldiers’ stats improve with experience
• Dynamic lighting for intense fire-fights
• Final Gameplay design and balance tweaks by the author of the popular original UFO: ET Bman Ease of Use Mod.