You knew pretty much nothing about the Halo universe after the first game. Who was the covenant, who built the halos, what is the flood. It was only really explained in halo 2 and then built on from there in the later games and books.
I remember lots of cool speculation after the first Halo on sites like halo.bungie.org. The universe at that stage was a total mystery.
You're not contradicting what I said. That's like saying you knew little about the Star Wars universe after A New Hope. It didn't matter. The story told in Halo was straightforward, easy to follow, compelling and self-contained. You wanted to know more about the universe. So far in Destiny I feel completely detached from the lore.