Superb comic conclusion!
Everything. The art is fantastic, and Fred Van Lente did a magnificent job thinking out this story and the art. This is a wonderful view at an expanded Halo universe, and stays true to every aspect of Bungie's brainchild. The character development is great, and the ending is perfection! Love the story, art, characters, and the action! I also like how the Elites also have character development, not just the Spartans and the AI. A shame both of the Elite Brothers *SPOILER AHEAD* died.
Nothing. Absolutely nothing. I couldn't find anything wrong with this comic, even when I was nitpicking at it.
If you're a Halo fan, definitely buy this. If you are a fan of Sci-Fi, definitely buy this. If you are a fan of comics, definitely buy this!