XCOM: Enemy Within trailer. br Shop CGR t-shirts and mugs! br br Classic Game Room’s CGR Trailers presents the announcement trailer for XCOM: ENEMY WITHIN from Firaxis Games and 2K Games. “Enemy Within” is an add-on for XCOM: ENEMY UNKNOWN that adds brand new features to the strategy game. This expansion pack will be available for the PC, PlayStation 3 and Xbox 360 video game platforms. This is the PEGI version of the announcement trailer.