How do you successfully survive a campaign in Left For Dead 2 ?

Must i finish the ';Dead Center'; campaign in one sitting to have successfully survived the campaign ? Because i finished it, but did one stage a day !!





(the achievement that unlocks when you finish a campaign remains locked for me !!)


(Why can't u save, what's the purpose of the ';Safe Room'; if i can't start from there tomorrow ?)How do you successfully survive a campaign in Left For Dead 2 ?
You have to finish them in one sitting.How do you successfully survive a campaign in Left For Dead 2 ?
Lol... ah man your priceless!





1 sitting on normal is about an hour.





Safe room is ment to be there to give you a small break and load up again, or on versus thats the part where you switch sides.





They do this becuase if they didnt, people would find a way to glitch the system so they DONT have to play the WHOLE campaign on expert or realism.





Dude its just an hour... HOW LONG ARE YOU TAKING??? 1 stage a day?? thats onlly like 15 minutes!!