What are the Campaign Meta-Games on Halo 3?

[vsb1002]

What are the campaign meta-games on halo 3. I am trying to get all of the achievements.

 

[Darren H]

When you go to launch a campaign chapter, go into settings and turn on campaign scoring. Then you get points for kills and headshots and the like, and you need to earn a set number of points to get the achievements.

Turning on skulls and playing on harder levels and finishing quickly gives you multipliers to your score. Playing co-op makes it more fun to do these, but you can do them by yourself.