Not too good personally
I like the fact you didnt just copy the main melody but you should have made the main melody ALOT LOUDER!
also the pad was much too fast. the chorus in the background isnt and hasnt been that fast since halo 1 so. the chorus in the background should be much slower. i like the fact that its in a trance/techno style but i prefer the rock one personally.
Last but not least the whole song didn't sound epic enough, sound effects ruined it in a sense. halo was always an emotional game and had epic exaggerated moments like a massive artifact being dug from the earth by an alien race. it needs an epic sound track this wasnt epic enough.
in the mix i could hear the main theme of halo 1-2 and of course 3 aswell as warrior which was used in sideskirts on halo 2 and Tsavo Highway on halo 3