no it can be played offline with custom rules including invincibility
You can't only in Halo Reach Firefight.
They only work in firefight. Also, they happen automatically in firefight
Your character can only talk in firefight.
No can only get firefight in halo 3 ODST
Yes, but only if it is in matchmaking.
Not much. You will only hear it in Firefight.
no it is not possible to be invincible in the campaign only in firefight and in custom game you can be invincible
you can't make a firefight map using forge, only mutiplayer
no, all there is not any flood in halo 3 odst firefight
No, firefight was not introduced until Halo ODST which was made after Halo 3. Only Halo ODST and Reach currently support it. Halo 4 will have a new game type called Spartan Ops which is similar.
Make firefight your own,being a helljumper in campaign,and jumping to your death in forge. Just put the disc in and start the game, you can play campaign, firefight, forge and custom games. You can not play matchmaking offline as that is multi-player only.
What the guy before me Obviously meant to say was, No, Halo ODST Offered you the beta. Halo reach came out 5 days ago, and once again you do not need XBL you can play halo reach without it, but on the otherhand, xbox live offers multiplayer coop campaign coop firefight and forge and custom games. So would buy XBL anyway. Gamertag Mr Gingee