The story of XCOM: Enemy Within takes place after the events of the original XCOM: Enemy Unknown . The player must once again defend humanity against an alien invasion, this time with the added ability to genetically modify soldiers and create MECs. These new features allow for greater flexibility and strategy in battle.
The gameplay of XCOM: Enemy Within builds upon the turn-based tactical strategy of its predecessor. The player must navigate the battlefield, use cover and resources effectively, and make tough decisions about which soldiers to deploy where. The addition of MECs and genetic modification adds a new layer of complexity to the game, requiring players to think carefully about their tactics and resource management.