I've read that there are 14 missions and that there are 12. So, not sure. However, it would depend on, also, how long a mission is and, probably, which difficulty setting you were playing at as well. --- Wurd77
12 missions is the official total I think. They take somewhere between 40 min and an hour to complete if you do everything right, don't die or screw up. Take into account some cinematics, failures, and multiple runs to complete the challenges or play the level differently and it should last a long time. Playing the game in coop usually increases the time it takes to finish as well as the AI are better at coordinating without talking than humans are.
on top of the missions, guerilla mode is said to take 20-30 hours to complete and thats also a fully coop mode. --- razielsdomain.forumotion.net A chilled out forum where basically anything goes. (Members have greater access and no ads).