can you open new levels on halo 3?

[woop]

like levels weapons and armor without being online or anything?

 

[Scott]

When you get sculls and achievements you get new armor but some achievements you have to get on xbox live. You cant unlock new weapons. Xbox just had a update for the heroic map pack and can be bought through the marketplace for 800 Microsoft points,you get three "levels" or "maps" the names are rats nest, foundry, and standoff but you have to have xbox live to get the maps.