X-COM: Terror from the Deep

X-COM: Terror from the Deep is a direct sequel to the earlier title X-COM: Enemy Unknown, sharing its core identity as a game of tactical combat and resource management. The narrative premise shifts the conflict to an aquatic setting, with alien forces emerging from Earth's oceans in the year 2040, four decades after the previous invasion was thwarted.

While the fundamental gameplay systems, user interface, and many enemy types remain largely unchanged from the original, key adaptations have been made for the new environment. This includes weaponry designed for undersea and terrestrial combat, with some new additions for close quarters. Missions take place both underwater and on land, and the overall experience is considered more challenging than the first game.