I have beaten the halo 4 campaign solo on legendary but was stupid to do it offline. For that I did not get the mark VI armor for a reward, but I did get the achievement. I was wondering if they were thinking of releasing an update so that things I do offline will count, or will I have to just do the campaign over again? Any information will be much appreciated. Thank you.
Just play Co-Op online so you can get marks saying you completed both solo and Legendary.
4 Player Co-Op Legendary can be done in ~3 hours.
How do I know? First time ever playing Halo 4 was at a friends party, and we beat the game in a little over 4 hours on legendary.