Before I begin if your reading this and expecting spoilers I’d recommend you not read any further…
So I never cared too much for games campaigns, but Halo is that exception!
I beat the Halo 4 Campaign today and it’s a blast! It reminded of Halo 2 because you hope around different places all the time, and Halo 3 because the action kept coming. But at the same time it had it’s own feel because of the living forerunner environments! While I loved the different environments it didn’t have good pacing and made it feel rushed, but overall I’d say the campaign is amazing, a must have game just for it, and 343I did a great job.
On the other hand while the storytelling was better than Bungies, it was still lacking because it assumed that you read the books and told it’s story accordingly (which Bungie was worst at). Even its true that the average Halo fan reads the books, i’m sure those fans would love to have a 10/15 minute cut-scene explaining important things like who the Didact/Librian are and they’re relations to ancient humans, what happened to Hasley, forerunner/flood war and other (important) things like that. If it’s so important then it should be in the game, and the books for further detail. If i remember correctly Master Chief mentions the Didact like he’s heard him a million times before, which doesn’t seem right. And the first confrontation between Master Chief and UNSC Infinity seemed anti climatic and a basically a casual way of saying “hey, how are you doing?”-- Also please don’t tell me Cortana died, I hope that’s a cliff hanger ending and we can find a way to tie things together. I love Cortana. 
I’ll leave some space in this article for MP and talk about it later!
Hope you guys like what i wrote, I tried to make it constructive, even in the criticism.