That's where I got my times from. I take all shortcuts, and pretty much rush through everything I can. That's why I said if you explore and kill everything it'll take about 30 hours.
For the entire series? I don't think the advice of a speed runner is necessarily helpful to the original poster. Since you probably know the maps so well, and what enemies to shoot, what switches to pull, it makes a huge difference.
For a newb Halo player, but experienced FPS player, I'd say Halo Campaigns are generally more in line with my play times:
On a per game Basis, in my experience:
Normal - 8 hours (Maybe 10-12 for Halo CE)
Heroic - 12-15 hours (I always start with Heroic solo, it just feels like the true Halo experience for me)
Legendary - 18-20+ depending on whether you are going solo or with experienced co-op friends. I wouldn't try this solo unless you want a serious challenge.
I feel like GAF Is exaggerating a lot of problems here. I've never had issue with the campaign, and I've seldomly had issue with multiplayer.
Great package in my opinion. I've completed every campaign up to 4, I'm half way through it now. Having a total blast.
I've been loving BTB and 2A playlists.
Edit: For comparison's sake, I had a far worse time with Unity.
Cool to hear you are having an awesome time. I think overall the issues are exaggerated, but I have first hand experience being on both sides of the working/not working camp.
- At work, I use a different X1, and have had a generally awesome experience with multi lately, but I did have more issues before patches.
- At Home, the game always worked decent online. It got better with the first patch or so, but the last patch actually borked my wait times. It's better with the latest patch, but not quite as good as it was.
So, I'm sure there are some people exaggerating, but I also think the game just legit still doesn't work that great for certain people on here.