This all depends on the game that you have... if it is a game such as blackops you can not play co-op mode unless you go online, you cant do so in campaign mode. if you have world at war on the other hand you are able to play in co-op mode.
no
yes every level you play single you play coop
NO
Yes you can play Tenchu Z coop but only for fun and online only.
You can't play coop on Red Dead Redemption or Undead Nightmare.
its called special ops
nope
how should i no lol
Yes there is.
That depends on what game system you have it for?
you can if you play coop campaign mode. The second player will be the arbiter
you get two profiles on and then go to campaign on coop