Here is a list of every medal you will find in Halo 3.
Full Halo 3 Medal List:

Linktacular!
Play in a matchmade game comprised of all Bungie.net users.

Death from the Grave!
Kill an opponent after you have died.

Killjoy!
End an opponent’s killing spree, any spree.

Steaktacular!
Luke owes you a steak dinner. Earned by winning a multiplayer game by 20 or more kills.

Killed Flag Carrier!
Kill the opponent flag carrier in CTF.

Killed Juggernaut!
Kill the Juggernaut in a Juggernaut game.

Killed VIP!
Kill an opponent’s VIP in a VIP game.

Flag Score!
Score the flag in CTF.

Killed Bomb Carrier!
Kill an opponent bomb carrier in Assault.

Bomb Planted!
Plant the bomb in Assault.

Laser Kill!
Get an opponent with the Spartan Laser.

Bulltrue!
Killed an opponent that was in the act of a sword lunge.

Grenade Stick!
Kill an opponent by sticking them with a sticky or brute grenade.

Perfection!
Win a slayer game with 15 kills or more without dying.

Assassin!
Hit and kill an opponent with a melee attack from behind.

Beat Down!
Hit and kill an opponent with a melee attack.

Incineration!
Kill an opponent with a flame-based weapon.

Highjacker!
Board a vehicle.

Skyjacker!
Board an aircraft by forcably removing the opponent in it.

Wheelman!
Be the driver of a vehicle when a passenger kills an opponent.

Extermination!
Get an overkill on he opposing team that results in all the team being dead.

Last Man Standing!
Be the last human in an infection game.

Oddball Kill!
Get a melee kill when holding the oddball.

Flag Kill!
Get a melee kill with the flag.

Sniper Kill!
Kill an opponent with the Sniper Rifle or Beam Rifle.

Splatter!
Hit and kill an opponent with a vehicle.

Splatter Spree!
Splatter 5 opponents in a row with a vehicle without dying.

Vehicular Manslaughter!
Splatter 10 opponents in a row with a vehicle without dying.

Hail to the King!
Kill 5 opponents in a row from inside the hill without dying before it moves.

Sniper Spree!
Kill 5 opponents in a row with the sniper without dying.

Sharpshooter! - Kill 10 opponents in a row with the sniper without dying.

Shotgun Spree!
Kill 5 opponents in a row with the shotgun without dying.

Open Season!
Kill 10 opponents in a row with the shotgun without dying.

Sword Spree!
Kill 5 opponents in a row with the sword without dying.

Slice ‘n Dice!
Kill 10 opponents in a row with the sword without dying.

Juggernaut Spree!
Kill 5 opponents in a row as the Juggernaut without dying.

Unstoppable!
Kill 10 opponents in a row as the Juggernaut without dying.

Infection Spree!
Kill 5 humans in a row as the zombie without dying.

Mmmm Brains!
Kill 10 humans in a row as the zombie without dying.

Zombie Killing Spree!
Kill 5 zombies in a row as the human without dying.

Hell’s Janitor!
Kill 10 zombies in a row as the human without dying.

Killing Spree!
Kill 5 opponents in a row without dying.

Killing Frenzy!
Kill 10 opponents in a row without dying.

Running Riot!
Kill 15 opponents in a row without dying.

Rampage!
Kill 20 opponents in a row without dying.

Untouchable!
Kill 25 opponents in a row without dying.

Invincible!
Kill 30 people in a row without dying.

Double Kill!
Kill 2 opponents within 4 seconds of the previous kill.

Triple Kill!
Kill 3 opponents within 4 seconds of the previous kill.

Overkill!
Kill 4 opponents within 4 seconds of the previous kill.

Killtacular!
Kill 5 opponents within 4 seconds of the previous kill.

Killtrocity!
Kill 6 opponents within 4 seconds of the previous kill.

Killimanjaro!
Kill 7 opponents within 4 seconds of the previous kill.

Killtastrophe!
Kill 8 opponents within 4 seconds of the previous kill.

Killpocalypse!
Kill 9 opponents within 4 seconds of the previous kill.

Killionaire!
Kill 10 opponents within 4 seconds of the previous kill.

Campaign Medals!

Superdetonation!
Score a kill by filling an opponent with enough needles to cause a detonation.

Plasma Combo!
Break an enemies shield and then score a Headshot.

Multikill!
Kill 3+ enemies in 1.5sec to earn a multiplier for all of them.

Headshot!
Kill an enemy with a Headshot.

 

http://www.the360forum.com/fps-action-discussions/14802-halo-3-new-medals-list.html

 

Halo 3 Full medal list courtesy of I snix I over at the 360 forums 

 

This entry was posted on Friday, October 26th, 2007 at 1:51 am and is filed under Xbox 360 Games. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.