no only online
I am sorry but there is no offline co-op
No
you cant. until dlc comes out.
Go to on line as usual, and go to your challenges and pick undead overrun.
You cannot play multiplayer mode without internet connections.
you cant
No there isn't and it is extremely unlikely that there will be
no it is on online mode
you need red dead redemption to play outlaws to the end
You can't play coop on Red Dead Redemption or Undead Nightmare.
Millions.
You can only play Red Dead Redemption on your Xbox 360 or PS3 on the Xbox Live or Playstation Network