Perhaps asking a stupid question here, but it just came up while my buddy and I were playing: How does each individual player's progress work when you're teamed up doing missions etc? Say I join my friend's game and complete missions, does the game treat a mission we both haven't done before as now done for both players, or just done for the person who's 'game' was joined? Is it just the same as if I was playing it solo?
Only reason I ask is because if I join his game then he leaves, it says he's disconnected and then I can 'leave group' which then seems to put me back into my own game. I'm a bit confused.