XCOM: Enemy Unknown, a turn-based tactics game developed by 2K Games and Firaxis Games, is available for free to Amazon Prime members with a GOG account until July 1. The game, originally released in 2012, is a reimagining of the 1994 classic UFO: Enemy Unknown and has a Metacritic score of 91. Players can expect around 30 hours to complete the main storyline, with completionists potentially investing up to 70 hours. The offer includes the “Complete Pack” version, which features the XCOM: Enemy Within expansion and all previously released add-on content.