Final battle fun

In the final ground battle, bomb straight through on a Ghost to get a Banshee, then fly up to the bridge and have fun whittling down the enemy with the sniper rifle and rocket launcher.

Enemy materialization

With the sniper rifle, if you quickly switch your view to the big rocks at the back after each kill, eventually you'll see enemy reinforcements suddenly materialize there. Obviously the Covenant have been watching Star Trek. "Plot a course for home Mr. Sulu. Wort wort wort factor 9."