Thanks to a little code adjustment though gamers can enjoy the higher resolution video renders. As it's discoverer pointed out, this inflates the game size needlessly for those downloading.
User 'loinbread' from Reddit calls the 720p videos "useless and unnecessary" as the 1080p clips are easily downscaled if they need to be for a sub-1080p monitor.
Apparently around 4GB of HDD space is 'wasted' by this duplication of video renders. In order to have the game play the higher 1080p clips you need to add a prefix tag of '1080_' to all the movie files located in the 'Steam > Common > Xcom-Enemy-Unknown > XcomGame > Movies' directory folder. Check out thefor more info.
XCOM: Enemy Unknown releases on Xbox 360, PS3 and PC October 12th in Europe.