'' XCOM '' was announced on April 13 , 2010 , for Microsoft Windows and Xbox 360 . The first gameplay demonstration was shown at E3 2010 . The game did not have any public promotion until a year later at E3 2011 . 2K Games announced that the game would be released March 6 , 2012 , the same day as competitor Electronic Arts released '' Mass Effect 3 '' . In early 2012 , the release was delayed until 2013 and then until 2K Game 's fiscal year 2014 , which meant that the franchise would be relaunched with Firaxis ' '' XCOM : Enemy Unknown '' instead . After another year of silence , 2K Games registered several new domains that hinted the game might return with a new title , possibly as '' The Bureau '' or '' What Happened in 62 '' . In April 2013 , the official website and all promotional videos and trailers for '' XCOM '' on YouTube were removed by the publisher , and 2K Games teased that the game had undergone a major evolution . '' The Bureau : XCOM Declassified '' was officially announced on April 26 , 2013 , for Windows , Xbox 360 , and PlayStation 3 . The game was released in North America and Europe on August 20 and 23 , respectively . TransGaming handled the game 's release for the OS X platform in December 2013
E3 2011
E3 2011
The Bureau: XCOM Declassified