Legendary Medals:
Hero - Win a game of infection as the last man standing.
Extermination - Wipe out an enemy team with at least one overkill.
Perfection - Play a game without dying with at least 15 kills.
Unfrigginbelievable - Kill 40 opponents in a row without dying.
Killionaire - Kill 10 opponents in the blink of an eye.

Multi-Kills:
Double Kill - Kill 2 opponents in the blink of an eye.
Triple Kill - Kill 3 opponents in the blink of an eye.
Overkill - Kill 4 opponents in the blink of an eye.
Killtacular - Kill 5 opponents in the blink of an eye.
Killtrocity - Kill 6 opponents in the blink of an eye.
Killimanjaro - Kill 7 opponents in the blink of an eye.
Killtastrophe - Kill 8 opponents in the blink of an eye.
Killpocalypse - Kill 9 opponents in the blink of an eye.

Sprees:
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 opponents in a row without dying.
Inconceivable - Kill 35 opponents in a row without dying.
Sniper Spree - Kill 5 opponents with the sniper without dying.
Sharpshooter - Kill 10 opponents with the sniper without dying.
Be the Bullet - Kill 15 opponents with the sniper without dying.
Shotgun Spree - Kill 5 opponents with the shotgun without dying.
Open Season - Kill 10 opponents with the shotgun without dying.
Buck Wild - Kill 15 opponents with the shotgun without dying.
Splatter Spree - Splatter 5 opponents using a vehicle without dying.
Vehicular Manslaughter - Splatter 10 opponents using a vehicle without dying.
Sunday Driver - Splatter 15 opponents using a vehicle without dying.
Infection Spree - Kill 5 humans as a zombie without dying.
Mmmm... Brains - Kill 10 humans as a zombie without dying.
Thriller - Kill 15 humans as a zombie without dying.
Zombie Killing Spree - Kill 5 zombies as a human without dying.
Hell's Janitor - Kill 10 zombies as a human without dying.
Hell's Jerome - Kill 15 zombies as a human without dying.
Stick Spree - Kill 5 opponents with grenade sticks without dying.
Sticky Fingers - Kill 10 opponents with grenade sticks without dying.
Corrected - Kill 15 opponents with grenade sticks without dying.
Assist Spree - Assist in killing 5 opponents without dying.
Sidekick - Assist in killing 10 opponents without dying.
Second Gunman - Assist in killing 15 opponents without dying.

Weapons & Style:
Splatter - Hit and kill an opponent with your vehicle.
Kill from the Grave - Kill an opponent after you have died.
Killjoy - End an opponents killing spree.
Grenade Stick - Kill an opponent by sticking him with a plasma grenade.
Beat Down - Hit and kill an opponent with a melee attack.
Oddball Kill - Get a melee kill while swinging the oddball.
Flag Kill - Kill an opponent with a melee attack using the flag.
Needle Kill - Score a kill by filling an opponent with enough needles to cause a detonation.
EMP Blast - Remove an opponent's shield with an EMP blast.
Assist - Assist a teammate in killing an enemy.
Revenge - Kill the opponent responsible for your previous death.
First Strike - Earn the first kill of a match.
Reload This - Kill an opponent while he is reloading.
Close Call - Kill an opponent while you are weakened and without a shield. Survive.
Pull - Kill an airborne opponent.
Showstopper - Kill an invisible opponent.
Rejection - Pick up an Overshield and survive massive damage.
Avenger - Avenge a teammate's death.
Protector - Save a teammate by killing his foe.
Firebird - Kill an enemy while you're airborne.
Assassin - Hit and kill an opponent with a melee attack while invisible.

Objective Medals:
Hail to the King - Kill 5 opponents in a row from inside the hill before it moves.
Flag Score - Complete a scoring flag capture in a Capture the Flag game.
Killed Oddball Carrier - Killed the opponent Oddball carrier in Oddball.
Killed Flag Carrier - Kill the opponent flag carrier in a Capture the Flag game.
Last Man Standing - Be the last human in an infection game.

Misc. Medals:
Avenge Me - You were avenged by a teammate.
Bros to the End - You were saved by a teammate.
Thank the Maker - Win a match with all leaders on the other team.
Linktacular - Play in a match composed of all [Z] members.