Lol, Cod sells 400+ copies because its easy to play and most people who play it are from the age range of 8-20, So of course they would sell the most copies, Most people can't play halo because its actually hard to play and to get use too. if halo didn't add anything it would get old fast, I believe the changes are great, Its still halo. Also cod is bad because they don't change anything up, from cod 4 to now its always been, Rearrange kill streaks, New maps/types, and rename the guns and add a few more. Thats it, same **** every game.