 The success of the main Halo trilogy spurred the creation of spin @-@ off games . Halo Wars is a real @-@ time strategy game developed by Ensemble Studios for the Xbox 360 . Set in the year 2531 , the game takes place 21 years prior to the events of Halo : Combat Evolved . Much effort was spent on developing a control scheme that was simple and intuitive , unlike other console strategy games . The game was announced at X06 , and released in February and March 2009 . 
