Halo: Reach Multiplayer Beta
From Halopedia, the Halo wiki
The Halo: Reach Multiplayer Beta is a phase in the development of Halo: Reach, produced by Bungie Studios and organized by Microsoft. The Beta will be released to the public on May 3rd 2010[1], and will be used to test different aspects of Halo: Reach multiplayer with the public, judging what to change based on public demand. The Beta will contain several maps and gametypes never seen before, and will showcase the new gameplay features in Reach.
There will be at least 16 player multiplayer, Theatre mode has been confirmed and will be returning, but it is unknown if it will be in the Beta or not. Bungie has also stated that the Beta will include many more vehicles, leading to believe that the maps will be larger and more vehicle based. The player will also be able to use a section of the character customization to customize their Spartan, but it is not known if Elites are Customizable as well. Little else is known about the Beta other than it will be released via the Halo 3: ODST disc.
