Bronze

The Geek
Complete the game on Recruits difficulty.

SNAFU
Complete SNAFU.

KISS
Complete KISS.

GNBN
Complete GNBN.

PFDL
Complete PFDL.

FUBAR
Complete FUBAR.

HUMINT
Complete HUMINT.

KATN
Complete KATN.

DOY
Complete DOY.

Getting Your Gun Off
Kill at least one enemy with every weapon in the game. (Single Player)

Frag Out!
Kill 20 enemies using grenades. (Single Player)

Never Knew What Hit Them
Kill 50 unalerted enemies. (Single Player)

Improv
Kill 20 enemies using explosive objects. (Single Player)

Suppressing Fire
Kill 20 enemies using blindfire. (Single Player)

Health and Safety
Blow up 20 fire extinguishers. (Single Player)

Military Budget
Kill 5 enemies with an assault rifle without reloading or changing weapons. (Single Player)

Come Get Some
Kill 5 enemies with a shotgun without reloading or changing weapons. (Single Player)

Ninja
Perform 3 kill moves in a row. (Single Player)

Curb-Stomper
Perform 5 finishing moves. (Single Player)

Chop-shop
Destroy 10 vehicles. (Single Player)

Over the Top
Throw an enemy over a ledge. (Single Player)

Not the Face
Smash an enemy's face into a wall. (Single Player)

Fresh off the boat
Play online once. (Multiplayer)

Spec Warrior
Kill 3 people in a row online. (Multiplayer)

SEAL Team Six
Play a Team Deathmatch to completion with at least 3 friends on your team.

Friendship is for suckers…
Kill someone on your friends list. (Multiplayer)

Keep your friends close…
Perform a kill move on a friend. (Multiplayer)

Decorated Veteran
Play 50 games online. (Multiplayer)

From Beyond the Grave
An enemy dies from your grenade…after you have been killed. (Multiplayer)

Host-me-up
Host a custom game to completion. (Multiplayer)

Silver

Shark Man of the Delta
Complete the game on Regulars difficulty.

Double Tap
Complete an entire level using only the pistol. (Single Player)

Now THIS is a Knife
Kill 30 enemies using kill moves. (Single Player)

Guns Don't Kill People, SEALS Do
Kill 30 enemies using sniper rifles. (Single Player)

Are These Guys For Real?
Kill 50 Speztnaz. (Single Player)

Migraine Breaker
Kill 50 enemies with head shots. (Single Player)

Gang Bang
Kill a group of four enemies with a grenade. (Single Player)

Dick Would Be Proud
Complete a mission without dying. (Single Player)

THREATCON
Place first in a Ranked Deathmatch game. (Multiplayer)

Smack The Rogue
Come first in 10 ranked Deathmatch games. (Multiplayer)

POTUS
Place first in a Ranked Team Deathmatch. (Multiplayer)

Special Warfare Group One
Be on the winning team for 10 TDM games. (Multiplayer)

One Man Army
Kill 200 enemies. (Multiplayer)

Gold

Demo Dick
Complete the game on Elites difficulty.

Legion of Merit
Finish each map in 1st place. (Multiplayer)

Platinum

Platinum
Earn this by collecting all the other trophies.

Source