Halo Tips

Stuff to notice
At the very start of the level in Keyes, go forward until you reach the first locked doorway on your left. Look down and you will see a upright assualt rifle on the ground. You can't pick it up and you can't blast it away with grenades. I don't know what it is supposed to be, but next time you play, take a look at it.

In 343 Guilty spark, notice how the Marines fire assualt rifles in rapid single shots like the flood rather than the three round bursts in other levels.