i have no clue it should be rated t 4 teen but the esrb said they reviewed the content and said it was m rated and refused 2 comment further
Various Halo games have been given the rating for different reasons, as listed on the box. Halo: Combat Evolved, Halo 2, and Halo 3: ODST had Blood and Gore, Violence, and Language listed as reasons, Halo 3 instead of Language has Mild Language, where as Halo: Reach simply has Blood and Violence. The factors from the ESRB may have gotten stricter over time however.
it seems however all the halo games WITHOUT the flood has only blood but no gore (other than odst?)