how com there is only 2 levels to play in the beta:sword base and powerhouse? isnt there supposeto be 2 other ones that are bigger and have vehicles?

Certain maps are tied to certain gametypes (Overlook to Generator Defense
and Boneyard to Invasion). Since gametypes will be releasing on a set
schedule (not all of them today) over the next two weeks, the maps tied to
those gametypes will come with them. You can see the schedule here:

http://www.haloreachbeta.com/content/al ... le-may-3rd