k so, the campaign disk contains no 'matchmaking.' You can play with friends, but you cannot search for teammates. and the reach beta. (seperate download, free.)
the "multiplayer" disk contains the exact same features as halo 3, but with an extra 3 maps (the other 3 mythics)
the "multiplayer" disk contains the exact same features as halo 3, but with an extra 3 maps (the other 3 mythics)