if your on about the career mode then you need to complete it and get all the Intel for the special ops mode to get 3 stars on all missions and i believe past level 15 on all levels and in multiplayer to prestige once and you get an extra 100% for ever other prestige you get
Complete all mission on veteran and collect all enemy Intel
finish on veteran every mission, and gather all Intel :)
100
yes complete the campaign.
If you complete the Single Player campaign on MW2 on the 2nd difficulty you are awarded 50% completion. To gain the other 50% you have to beat the campaign on the "Hardened" and "Veteran" Difficulties.
yes you have to complete the campaign then do mission select then do the bonus one
No, But there is a spec ops type thing which is like campaign but is muliplayer.
You can't.
yes.
some guy you have to escort
No, MW2 does not have 2 player campaign. Although, it has 2 player Special Ops. Black Ops also has two player online.
no, it would not be as good.
if you collect all of them it gives you cheats in the main campaign
Nope, so far only World at War has co-op campaign.