 Bungie began developing Halo 3 shortly after Halo 2 shipped . The game was officially announced at E3 2006 , and its release was preceded by a multiplayer beta open to select players who purchased the Xbox 360 game Crackdown . Microsoft spent $ 40 million on marketing the game , in an effort to sell more game consoles and broaden the appeal of the game beyond the established Halo fanbase . Marketing included cross @-@ promotions and an alternate reality game . 
