2K games, maker of BioShock and XCOM have released a new “expansion” for the popular XCOM: Enemy Unknown titled Enemy Within. While the company calls the game an “expansion,” the term “sequel” might be more apt for the iPhone version, which functions as a standalone app rather than an add-on to the previous game.

Enemy Within, which was released for PCs exactly one year ago this past Tuesday to high praise from players, builds on the gameplay of Enemy Unknown, but adds several features and updated mechanics, including new enemies, weapons, abilities, and even an expanded story.

XCOM: Enemy Within is available on the App Store for $12.99. In lieu of a change log, the full App Store description, including a detailed list of the new content, in included below:

• New Soldier Abilities: Build new base facilities to unlock unearthly new capabilities for XCOM’s soldiers. The Genetics Lab will allow soldiers to receive powerful genetic modifications, and the Cybernetics Lab allows soldiers to use devastating mechanized cybersuits in battle.

• New Weapons and Equipment: Give your operatives an extra tactical edge with new projects from your engineering team and the Foundry.

• New Enemy Threats: Adopt new tactics to counter the threats from two new alien types and a deadly new organization known as EXALT.

• New Strategic Resource: A valuable new alien resource, known as Meld, has been discovered. Secure it on the battlefield, research a new technology to unlock its power, and use it carefully back at base to unlock new upgrades and weaponry.

• New Story Elements: Investigate a terrifying threat in an abandoned fishing village, and defend the XCOM headquarters from alien attack in a series of new plot-driven missions.

• New Multiplayer maps, units, and abilities: Create your custom squad from a wider array of options and dominate your opponent in intense, one-on-one, turn-based matches.