Huh. Now that you mention it, if I wasn't so well versed in Halo, that game would have lost a lot of it's punch.
Like, the whole point of New Alexandria was to try to tell the player that IF YOU FAIL HERE, THIS WILL BE EARTH. But if I didn't know about all the Halo back story, it would have been just another destroyed city.
That being said, Bungie did say that this was a game for Halo fans. But that is sort of a cop-out: Fall of Reach was basically required reading for that game, and that's not a good thing. I should not need to read a book to understand a Prequel. The fact the Fall of Reach was really good does not excuse them.
I, for one, would not have minded if the game was a little longer, if it would have sat down and explained some things to new players. I bet Dr.Hasley came right out of left field for people who have't read the books, considering the fact that she hasn't been mentioned in any other Halo game.