I've seen a couple other people post about finishing the campaign and not getting the achievement. In most cases, it's because one of the missions didn't get registered as being finished...even though they were able to keep right on playing through the end. This makes some sense...otherwise you could "unlock" just the final mission playing co-op with a friend, then finish it on your own to get the campaign achievement. But not registering the completion in the first place is still a bug, so I'm reporting my sequence of events as best I remember it (it was late at night so the specifics of exactly where I stopped each session are a little fuzzy).
Playing through Halo 4 campaign in multiple sittings:
-played missions 4-6 (partway)
-turned off xbox (not save and quit)
-when I resumed the campain, it stared me back on 4 (where I had started the day before)
-I quit and found that I could select where I left off in the campaign hub
-finished the campaign but...didn't get any of the achievements for finishing the campaign
On investigating I found:
No achievement for finishing chapter 6
When I selecting where to start in the campaign hub, I could select all the rally points in mission 6
...so I selected the last rally point and finished the mission again...still no achievement, still no finished mission in hub
Did some research, saw a couple other people complain about missing saves/achievements, but no fix other than "play it again"
So I played mission 6 again...sortof:
http://www.youtube.com/watch?v=-uFKRjpD1Jg
Thank goodness for shortcuts because I did NOT want to go through the gondola sequences again.
...when I finished, it registered and posted the mission and campaign achievements
If anyone else had a similar experience, please post it. I suspect it has to do with quiting by turning off the xbox instead of going through the "Save and Quit" sequence, so anyone who can confirm or refute that would be helpful.
