: I've never read any of the Halo books. I know a few things about the EU from
: reading summaries online and hanging out with fellow Halo nerds. I
: probably know a bit more about Halo lore than the typical Halo player.

: That said, I had a hard time enjoying Halo 4's campaign because of this:
: "I thought we had a truce with the Covenant?"
: "A lot can happen in four years."

: The Elites, who had always had a united front in Halo 2 and Halo 3, were now
: fighting us? After all the work we had done as the Arbiter and the Chief
: in the previous games, now we were enemies again? I spent most of the game
: wondering why we were fighting who I could only presume were the Arbiter's
: friends.

I've never really gotten this gripe (I've certainly heard it from many people.) As Cortana says, "a lot can happen." If you haven't read the books then you're as out-of-the-loop as Chief, and it doesn't exactly strain incredulity to think that humans and Elites might have lapsed back into war. You know, they only really buddied up to stop the end of the universe.

As for the rest, either you make as Grizzlei said MGS-level stupefying cutscenes, or you put in clues, streamline things, and assume your audience has a brain to make connections, because otherwise any game is going to start collapsing under the weight of trying to cater to lowest common denominators of players.