Co-op question

[The_UD]

How does the co-op campaign work? Is it like in Conviction where you can just jump straight in from the menu or do you have to unlock the co-op levels through the single player campaign?
I have been reading some reviews and they say that there isn't a menu system anymore but you have an interactive base where you can choose your missions or whatnot. They also said that talking to some people will unlock their co-op missions.
I plan on buying this game because I'm going to visit a friend in a different city and were planning on playing through the co-op campaign while I'm there. Basically, I want to know if we'll be able to get straight into the co-op or if I should pick it up before I go to play through the single player story that way I have all of the co-op stuff unlocked and ready to go.

Thanks

 

[Bjf3359]

the 3 main side characters all have their own set of 4 co-op missions the briggs missions you have to play co-op and the other 2 you can play either single player or co-op. at the start of the game one mission from each character is unlocked and as you complete missions more will be unlocked