completed halo 3 but how?

[djb]

I have just completed halo 3 on the easy level, but how do i restart the game on normal level without losing the easy level ?

 

[Matt]

I'm pretty sure you just go under campaign then under difficulty select which difficulty you want, then start it. Your levels you completed should be saved.

 

[Dawgpound7000]

Yeah you can pick the difficulty and what lvl you want to play. (pick any lvl you want if you beat the game, which you have so you can )