Halo 3 allows for 2-player co-op on one console, or 4-player competitive (Slayer, CTF, etc). Utilizing LAN features (connecting 2 Xbox 360s together using a cross-over LAN cable or connecting 2 or more Xbox 360s to a switch or router), Halo 3 allows for 4-player co-op (up to 2 players per Xbox 360) or 16-player competitive.
no you cant
yes
Yes if you have a friend or family member willing to play with you yes but it has to be on the 360 itself you can't connect to your friends xbox offline
No, they are two completely different multiplayer setups.
You can play Halo 4 multiplayer offline in split-screen with up to four people on one Xbox. You need will need four controllers, and to do it, you need to go to "Infinity" from the main menu, then choose "War Games," then choose "Custom Game." To do this, all players will need to sign in to a profile or use a temporary profile (an actual profile is recommended, as your progress isn't saved with a temporary profile)
There is multiplayer in halo 4
You can get 43 achievements offline on halo 3 im not sure on odst.
No, halo 3 forge is not offline, you may play it online with friends or others.
you can get all of the skulls on multiplayer. =)
You get the Halo 3 ODST campaign and Halo 3 multiplayer. Nothing else.
offline firefight coop surpports online 16 players, system link 16, and 4player split screen.
yes only multiplayer has the new map packs but you can get them in the DLC