What is the hardest level in halo3?

Answer 1

The hardest level, in my opinion is the 9th mission, cortana, unlike in many of the other missions, you have no friendly ai to help you, you are on your own and are often running out of ammo, since the flood don't drop it too often, not only this, but its also maze-like and confusing at times, the tunnels and organic caverns you go through are very confusing and this mission is where I die the most