Here's the "Last Defence" trailer of The Bureau: XCOM Declassified.

Also check out this hands-on preview of the game from Rev3Games:

The Bureau is an upcoming X-COM game in development by 2K martin for the PS3, Xbox 360 and PC. The game has been in development since 2006 and was unveiled as a first person shooter back in June 2010. Since then it has been constantly delayed and changed until April 2013 when the game was rebranded as The Bureau: XCOM Declassified. The game is currently due to be released August 20 2013 in the US.