It’s not too bad, give it a go!
Reach the rank of Captain in the UNSC. - Halo: Reach
After 9/25/08, complete Halo on 4-player Legendary LIVE co-op, with Iron, and everyone in Ghosts. - Halo 3
Finish the final mission of the Campaign on Normal, Heroic, or Legendary. - Halo 3