Campaign scoring
From Halopedia, the Halo wiki
Campaign Scoring, also known as Meta-game, is an optional game feature for the campaign mode of Halo 3.
If one chooses to play a Meta-game, one plays a normal campaign mission (single player or cooperative), but progress is scored by points for notable activities. Having skulls activated increases the amount of points that you gain, as well as accuracy and kill count. Different enemies give different points as do headshots (and assumably any other kill that would be worth a medal). Betrayals will cause negative points so cooperative work will be necessary. To find out more about campaign scoring, listen to mission Design Lead Paul Bertone on the Bungie podcast. [1]
Point Values
In the Meta-game you earn points by killing enemies, here is a list of their base value (what you get per kill without any extra modifiers).
Enemies
Flood
Specialists
- Pure Form Stalker - 20
- Pure Form Ranged - 30
- Pure Form Tank - 50
Infantry
- Flood Carrier Form - 10
- Combat Form (Human,Brute,Elite) - 10
Covenant
Heroes
- Brute Chieftain (Weapon/Armor Variants) - 150
Leaders
- Brute Captain - 50
- Brute Captain Major - 50
- Brute Captain Ultra - 50
Specialists
- Brute Stalker - 30
- Brute Jump-pack - 30
- Brute Bodyguard - 30
- Jackal Sniper - 20
- Grunt Heavy - 10
- Grunt Spec-Ops - 10
- Hunter - 150
Infantry
- Brute Minor - 20
- Brute Major - 20
- Brute Ultra - 20
- Grunt Minor - 10
- Grunt Major - 10
- Jackal Minor - 15
- Drone Minor - 10
- Drone Major -10
Forerunner
Infantry
- Sentinel Aggressor Minor - 5
Vehicles
Light
- Shade - 50
- Ghost - 100
- Chopper - 100
Standard
- Prowler - 150
- Banshee - 100
Heavy
- Wraith (Both Variants) - 200
Giants
- Scarab - 500
Multipliers
In the meta game, the difficulty selection, active skulls etc. This will help you determine the score multiplier for that session.
Difficulty Multipliers
- Easy - 0.25x
- Normal - 1x
- Heroic - 2x
- Legendary - 4x
Skull Multipliers
- Iron - 3x
- Black Eye - 1.5x
- Tough Luck - 1.5x
- Catch - 1.5x
- Fog - 1.5x
- Famine - 2x
- Thunderstorm - 1.5x
- Tilt - 2x
- Mythic - 2x
Time Multipliers (N/A)
References
http://www.bungie.net/online/default.aspx
http://www.bungie.net/News/content.aspx?type=topnews&link=h3campaign