UPDATE 4.30pm UK: Halo developer 343 Industries has now said it is working on a way to replay campaign missions in the future – although there’s no word on when that might be.
“We haven’t announced a date but that is being worked on,” 343 Industries associate creative director Paul Crocker told The Verge. “We want to have replay that works well, and when you have a more open game, it gets a lot trickier.