Disclaimer: I love the Multiplayer of the game, and this is just an opinion on the story.
I know marketing is meant to make you want to buy a game, and I know that it sometimes created by people that are external to the game development studio, but the entire ad campaign (Hunt the truth etc) kind of ruined the story for me. I feel that this wasn’t the story we ended up playing.
Most of the trailers prior to the games launch, highlighted the chief going rouge and Osiris having to go on the ‘greatest hunt ever told’ to get him. Personally, it felt like the chief was just following his vision and there wasnt much truth, or rather a very compelling truth to hunt. The live action trailer also felt like it had nothing to do with the story. Someone in the trailer says that "chief is gone and his setting these things loose (the guardians). Now that doesnt happen in the story, nor does any battle in the in the game take place in a destroyed human city like the trailer depicts. Now before you say this was just a trailer, bear in mind that this setting is even on the damn boxart cover. I was hoping for this kind of setting in the final mission, and not yet another forunner location, just like halo 4 did.
The other 2 trailers of locke and chief walking towards one another talking, is also not even felt as a theme in the game. Their hostility towards one another is barely there.
It must be said that I enjoyed the time getting to know Osiris, even if it was merely by in game chatter, but I wish we got to know blue team a bit more.
Maybe I just bought into the hype before the game came out, but I feel this isnt the story that was promised in all those vidocs and trailers.