Halo 3 no more - meet Forerunner@ 2006/03/17
The source reports that the game will feature "huge persistent worlds" using a modified Halo 2 engine. The main campaign will still feature Master Chief and will showcase 4-player co-op. The missions, however, will not be linear, nor will objectives been required. For example, if players are tasked with capturing a weapons depot, but decide to forego the assignment, then they will loose the opportunity to seize the additional weaponry and, in effect, will hand these weapons over to the enemy.