Sorry to ressurect, but I am having problems with ODST. I co-op the campaign on legendary and beat it, however I didn't get the achievements. I saw the engineer light the cigar, waited through all of the credits and saw the prophet with the other engineers. Then it took us back to the lobby and thats it. We have done this twice although the second time we skipped the cut scenes at the end still to no avail. Anyone else run into this?
