I liked it, but one thing bothered me.

The halo rings ended up at all of the covenant species home worlds? And all of them where 'reclaimers' too?

The whole forerunners 'saving and repopulating' species was a little under explained if you ask me.

And if the covenant species had halo's of their own, and they where 'blessed' by the forerunners like the Humans, why didn't they activate their 'great journey' themselves. Or for that matter go looking for more halo's in general.

Other then that I really liked it, art was good...etc liked the look of the forerunners too and still managed to keep the sense of mystery.

I think the whole flood dying when the halo's where activated was either killing the sentient beings of the flood hairacy or it was just for visual effect to show what would happen to the floor, for the sake of the story.