I got the achievements for beating the campaign on Legendary, but it still says on my service record that I only started the campaign on Legendary. It appears that I missed one mission (the VERY FIRST one). Since I played the game on co-op, I'll need to beat it with another player. Does anybody have about five minutes to do it with me?
Although I'm not sure: does beating the campaign on co-op count as officially completing the campaign?