i was playing co-op with my friends and we finished the campaign and i never got the achievement for beating it on legendary and they did. we did every mission together and i looked over my missions and it says i beat reclaimer on normal! normal i never played the campaign on co-op on normal! will someone tell me this is just a glitch and it will be fixed please because i really don’t wanna have to play through that long mission again
The only thing you can do is play the mission again.
I don’t know why you think it’s so bad, because the campaign is a lot of fun.
have you beat it on legendary yet? if you haven’t then you wouldn’t understand how hard it is to beat its really time consuming
Go to commendations, select player, select campaign, and see if any of them are incomplete.
ok thanks for the reply i will check!
Just be thankful that it isn’t Forerunner that you have to redo. 
LOL so true!
thank you everyone who commented!! i just sucked it up and played it again and it worked this time :)!! and as pulse said i shouldn’t complain this campaign is amazing!!