Mutators (and how to unlock them)Jaguar said:You'll be able to unlock some skins by getting certain achievements.
http://multiplayerblog.mtv.com/2011...eapon-skins-characters-mutators-executions/2/
COMET (Easier)
Earn the gold Shock Trooper medal (for earning a certain number of First Blood ribbons)
As you roadie run, you'll build up energy, letting you ram into enemies.
INSTAGIB MELEE (Easier)
200 Wretch kills
Melee attacks explode enemies
SUPER RELOAD (Easier)
Earn the bronze Master-At-Arms medal (100 kills with each of the starting 5 weapons)
More damage and clip size for an active reload.
INFINITE AMMO (Easier)
Earn the Combat Engineer pin 100 times (worked on 5 fortifications in one deployment in Horde)
Infinite ammo for all weapons.
BIG EXPLOSIONS (Easier)
Earn the Hail Mary pin 100 times (Boomshot kill from over 200 yards away)
Bigger explosions, natch.
ENEMY REGEN (Harder)
Earn the silver Aficionado medal (for playing a certain number of chapters in Arcade mode)
Enemies will regain health over time if you don't kill them.
VAMPIRE (Harder)
Earn the Executioner pin 100 times (for having the most executions in a match)
Your health does not regenerate automatically, but you do earn health for dealing damage.
MUST ACTIVE RELOAD (Harder)
Earn the silver Active Reloader medal (for actively reloading a certain number of times)
The only way to reload is to perform an active reload.
FRIENDLY FIRE (Harder)
Complete the campaign in 4-player co-op
Teammates can cause damage to each other.
BIG HEAD (Fun)
Earn the gold Horder medal (for playing a certain number of waves in Horde)
Giant heads, "NBA Jam" style.
PINATA (Fun)
Earn the gold Investor medal (for repairing and upgrading a certain number of defenses in Horde)
Tokens drop from every kill. Picking them up earns you points.
FLOWER BLOOD (Fun)
Earn the silver King of COG medal (for earning a certain number of total points in Arcade)
All blood effects are replaced by pretty flowers.
HEADLESS CHICKEN (Fun)
Unlocked from the start
Enemies attack each other for several seconds after they lose their heads.
LAUGH TRACK (Fun)
Earn the bronze medals for Tour of Duty (Finish Campaign on Casual), For the Horde (Finish Horde on Casual), I'm A Beast (Finish Beast on Casual) and Warmonger (Finish Arcade on Casual)
Adds an audible laugh track to the game
Earn the gold Shock Trooper medal (for earning a certain number of First Blood ribbons)
As you roadie run, you'll build up energy, letting you ram into enemies.
INSTAGIB MELEE (Easier)
200 Wretch kills
Melee attacks explode enemies
SUPER RELOAD (Easier)
Earn the bronze Master-At-Arms medal (100 kills with each of the starting 5 weapons)
More damage and clip size for an active reload.
INFINITE AMMO (Easier)
Earn the Combat Engineer pin 100 times (worked on 5 fortifications in one deployment in Horde)
Infinite ammo for all weapons.
BIG EXPLOSIONS (Easier)
Earn the Hail Mary pin 100 times (Boomshot kill from over 200 yards away)
Bigger explosions, natch.
ENEMY REGEN (Harder)
Earn the silver Aficionado medal (for playing a certain number of chapters in Arcade mode)
Enemies will regain health over time if you don't kill them.
VAMPIRE (Harder)
Earn the Executioner pin 100 times (for having the most executions in a match)
Your health does not regenerate automatically, but you do earn health for dealing damage.
MUST ACTIVE RELOAD (Harder)
Earn the silver Active Reloader medal (for actively reloading a certain number of times)
The only way to reload is to perform an active reload.
FRIENDLY FIRE (Harder)
Complete the campaign in 4-player co-op
Teammates can cause damage to each other.
BIG HEAD (Fun)
Earn the gold Horder medal (for playing a certain number of waves in Horde)
Giant heads, "NBA Jam" style.
PINATA (Fun)
Earn the gold Investor medal (for repairing and upgrading a certain number of defenses in Horde)
Tokens drop from every kill. Picking them up earns you points.
FLOWER BLOOD (Fun)
Earn the silver King of COG medal (for earning a certain number of total points in Arcade)
All blood effects are replaced by pretty flowers.
HEADLESS CHICKEN (Fun)
Unlocked from the start
Enemies attack each other for several seconds after they lose their heads.
LAUGH TRACK (Fun)
Earn the bronze medals for Tour of Duty (Finish Campaign on Casual), For the Horde (Finish Horde on Casual), I'm A Beast (Finish Beast on Casual) and Warmonger (Finish Arcade on Casual)
Adds an audible laugh track to the game
The rest of the unlocks are pretty straight forward.