Microsoft has announced that all the players who would pre-order Halo 3: ODST, set to be released for the Xbox 360 on September 22 for the price of 39.99 dollars, should get a chance to unlock Sgt. Johnson as a character that can then be used in the Firefight game mode.

Johnson is one of the big icons of the Halo series, having a lifetime experience of taking on both the Covenant and the Flood, at times alongside the legendary Master Chief. It's not clear whether he will offer any gameplay advantage or whether he will just use a unique character skin.

Firefight is one of the new additions to the game, pretty similar to what Epic delivered in the Horde mode for Gears of War 2. Players will team up in order to defend a position as waves after waves of enemies, getting ever tougher, assault them. Cooperation is key to survival and becomes more important as the Halo 3 skulls activate, changing the gameplay mechanics in Firefight.

The story of ODST will be centered around Shock Marines, the elite troops of the United Nations Space Command, who are dropped in New Mombasa and need to link up with one another while figuring out why the Covenant has taken over the city. Master Chief will not make an appearance in the title, which might mean that fans of the universe will not be as quick to pick it up.

Still, Microsoft has thrown in another powerful incentive by announcing that all those who would buy Halo 3: ODST would get a chance to enter the beta of the next Halo title, called Reach, developed by Bungie and Microsoft, which should be released in the fall of 2010. This one will apparently feature a multitude of Spartans, Master Chief being among them. The beta will probably take place sometime in the summer of 2010.