Museum bonus level

Successfully complete the game to unlock the Museum bonus level. Go to the single player missions, select the new "Museum" mission at the bottom, and choose a difficulty. When the level begins, it is recommended you first study the layout. Get two weapons, and max out your ammunition through the crates supplied. Go to the desks by the entrance to the rooms. On the desks there is a red bell that is labeled "Don"t Press". Once you press this button, enemies will begin coming to life in one room area at a time. About thirty people (all characters from the game) will try to kill you. You will hear a sound once that wave is completed. There are two waves of kills needed to complete it. Note: There are three rooms, one of which nothing happens in. Do not bother shooting anyone prior to using the bell, as it will not count.

Extra Custom Class slots

Reach Level 70 in Multiplayer mode to unlock Prestige mode. Reach the indicated Prestige level to unlock the corresponding Custom Class slot.

Sixth Custom Class slot: First Prestige
Seventh Custom Class slot: Third Prestige
Eighth Custom Class slot: Fifth Prestige
Ninth Custom Class slot: Seventh Prestige
Tenth Custom Class slot: Tenth Prestige

Professional perks

Successfully complete the indicated task to unlock the corresponding Professional perk:

Bling Pro: Get 200 kills while using a weapon with two attachments. Its effect is two primary weapon attachments and two secondary weapon attachments.
Cold-Blooded Pro: Destroy 40 enemy Killstreak rewards while using the Cold-Blooded perk. Its effect is undetectable by UAV, air support, sentries, and thermal imaging; and no red crosshair or name when you are targeted.
Commando Pro: Get 20 melee kills while using the Commando perk. Its effect is increased melee distance and no falling damage.
Danger Close Pro: Get 100 kills with explosives while using the Danger Close perk. Its effect is increased explosive weapon damage and extra air support damage.
Hardline Pro: Get 40 Killstreaks while using the Hardline perk. Its effect is that Killstreak rewards require one less kill and Deathstreak rewards require one less death.
Lightweight Pro: Run 30 Miles while using the Lightweight perk. Its effect is move faster and quick aim after sprinting.
Marathon Pro: Run 26 Miles while using the Marathon perk. Its effect is unlimited sprint and climb obstacles faster.
Ninja Pro: Get 50 close range kills while using the Ninja perk. Its effect is invisible to heartbeat sensors and silent footsteps.
Scavenger Pro: Resupply 100 times while using the Scavenger perk. Its effect is resupply from dead enemies and extra magazines.
Scrambler Pro: Get 50 close range kills while using the Scrambler perk. Its effect is jam enemy radar near you and delay enemy claymore explosions.
Sitrep Pro: Destroy 120 detected explosives or tactical insertions while using the Sitrep perk. Its effect is detect enemy explosives and tactical insertions and louder enemy footsteps.
Sleight Of Hand Pro: Get 120 kills while using the Sleight Of Hand perk. Its effect is faster reloading and aiming.
Steady Aim Pro: Get 80 hip fire kills while using the Steady Aim perk. Its effect is increased hip fire accuracy and longer hold breath duration.
Stopping Power Pro: Get 300 Kills while using the Stopping Power perk. Its effect is extra bullet damage and extra damage to enemy vehicles.

Multiplayer weapons and equipment
Reach the indicated level in Multiplayer mode to unlock the corresponding item:

Assault rifles

FAMAS: Level 1
M4A1 carbine: Level 4
SCAR-H: Level 8
TAR-21: Level 20
FAL: Level 28
M16A4: Level 40
ACR: Level 48
F2000: Level 60
AK-47: Level 70
Handguns

USP .45: Level 1
.44 Magnum (Colt Anaconda): Level 26
M9: Level 46
Desert Eagle: Level 62
Launchers

AT4-HS: Level 1
Thumper x2 (M79 grenade launcher): Level 14
Stinger: Level 30
Javelin: Level 50
RPG-7 x2: Level 65
Light machine guns

L86 LSW: Level 1
RPD: Level 4
MG4: Level 16
AUG HBAR: Level 32
M240: Level 52
Shotguns

SPAS-12: Level 1
AA-12: Level 12
Striker: Level 34
Ranger: Level 42
M1014: Level 54
Winchester 1887: Level 67
Sniper rifles

CheyTac Intervention: Level 1
Barrett .50 caliber (M107): Level 4
WA2000: Level 36
M21 EBR: Level 56
Submachine guns

UMP .45: Level 1
MP5k: Level 4
Vector: Level 12
P90: Level 24
Mini Uzi: Level 44
Secondary weapons

PP-2000 machine pistols: Level 1
Glock 18: Level 22
M93 Raffica: Level 38
TMP: Level 58
Other

Frag grenade: Level 1
Semtex: Level 1
Throwing knife: Level 7
Tactical insertion: Level 11
Blast shield: Level 19
Claymores: Level 31
C4: Level 43

Kill streak bonuses

Get the indicated number of consecutive kills in Multiplayer mode to get the corresponding bonus:

UAV: 3 (reveals enemies on mini-map)
Care Package: 4 (ammo or killstreak air drop that can be collected by anyone)
Counter UAV: 4 (disables enemy radar)
Predator: 5 (guided missile)
Sentry Gun: 5 (airdropped weapon)
Precision Airstrike: 6 (select a location to bomb)
Attack Helicopter: 7 (helicopter backup)
Harrier Strike: 7 (select a location to bomb and defend with a Harrier)
Emergency Airdrop: 8 (four ammo or killstreak air drops that can be collected by anyone)
Pave Low: 9 (armored helicopter backup)
Stealth Bomber: 9 (undetectable airstrike)
AC-130: 11 (operate a plane gun)
Chopper Gunner: 11 (operate a helicopter gun)
EMP: 15 (disables enemy electronics)
Tactical Nuke: 25 (kills everyone)

Sniper camouflage

Successfully complete the "Ghillie In The Mist" challenge in Multiplayer mode with the indicated number of one-shot kills with sniper rifles to unlock the corresponding Ghillie camouflage suit:

Arctic camo: 50 one-shot kills with sniper rifles
Desert camo: 200 one-shot kills with sniper rifles
Urban camo: 100 one-shot kills with sniper rifles

Intel locations

Search the indicated locations to find all 45 Intel laptops:

Act I: S.S.D.D.

1. The Intel is under the watch tower, straight across from the entrance to the obstacle course.

Act I: Team Player

2. The Intel is in a classroom. Someone will announce "I think I saw one go in that classroom", and your team will go in. It is on the right wall as you enter, on a desk by the barrels.

3. As you exit the school, it is on a crate directly outside, next to a taxi.

Act I: Cliffhanger

4. Directly in front of you when Soap tells you to go ahead alone is a guard tower. Go up the ladder to find the Intel on the catwalk.

5. When you are about to enter the building with Soap, go to the previous building in the alley where the Jet is inside the hanger. Break out the window to find the Intel inside.

6. During the snowmobile sequence, when you are approximately 1850m from the finish, stop. Look for a small wooden fence surrounding some trees in the middle of the path in front of you, and a small wooden building up a hill to the right. The Intel is on the ground inside the fenced area with trees. Just run over the Intel to pick it up.

Act I: Takedown

7. Using the map, go towards the south-west corner when you enter the favela. You should find a motorcycle leaning against a building. In front of it, there is a building with an angled wall and a large window in the wall. Go through the door to the right of that window to find the Intel inside.

8. When you go through the alley and see the building with the ladder on the wall, go up it and through the door. The Intel is on a table inside.

9. Directly across from the previous Intel is a building with a small set of wooden stairs. There are a few guys inside you have to kill. The Intel is inside the building on a nightstand next to the bed.

10. Towards the end of the chase, off an alley, go in the building on the right side of the path. Go downstairs to find the Intel between two beds.

Act II: Wolverines!

11. The Intel is on the counter in the gas station after you go through the alley.

12. The Intel is inside CRB Financial (across from Nate"s Restaurant), near the front door, under a sign labeled "Online Banking".

13. The Intel is on a table inside Taco To Go. Enter the building through the blown up corner.

14. The Intel is inside a dumpster (in a small brick enclosure) on the east side of Burger Town. It is visible from the Burger Town roof ladder.

Act II: The Hornet"s Nest

15. Near the beginning, after you move forward from the first building, go inside the house to the right of where Soap stops in the road (there is a blue car in the garage). Go past the blue car and into the kitchen to find the Intel on the table.

16. After clearing the small lot (has a bunch of appliances and cars), instead of going right up the stairs between buildings, go left around the three-story house (floors are colored red, yellow, red), and look in the little hut attached to its side to find the Intel on some barrels.

17. As you move up the sloped street, there is a blue car on the right side of the street. In the building on that side is the Intel up on the second floor on the table.

18. When you enter the last open lot and are supposed to go up on the roof, turn to the right, and look in the window behind the goal fence to find the Intel inside a window.

Act II: Exodus

19. In the apartment office, near where the enemies are first repelling in from a chopper. It has red walls and blue curtains inside. The Intel is on the desk.

20. In the right-side building of the structure that forms an arch over the road (has toll booths), on a desk directly to the right as you enter.

21. After you cross the bridge, go into the second house on the right side of the street. Enter from the front door, then go to your right and up the stairs. The Intel is on a yellow couch above those stairs.

Act II: The Only Easy Day... Was Yesterday

22. In the room before you go back outside (shortly after breaching), the Intel is on one of the metal racks against the wall.

23. After executing "Plan B", in the room Soap goes into on the right, the Intel is on a metal rack inside the door.

24. After clearing outside, when the team starts going up the stairs, enter the room to the right (you were probably in this building before when you were told to take cover), and look under the stairs on some wooden palettes to find the Intel.

Act II: The Gulag

25. As your team moves towards the arch with the red light, go to the stone stairs before it, and look inside the room on the far wall to find the Intel on some filing cabinets.

26. The Intel is on a desk behind the large wall of monitors you encounter on your way through.

27. After you get the riot shield and leave the room where you got it, turn left, and go down the hallway. In the first open cell on the right-side wall is the Intel on a desk.

28. Once you find the person you have been looking for, turn to your left to find the Intel on the desk.

Act II: Of Their Own Accord

29. Inside the elevator that keeps trying to close (in the hallway after you enter the building), the Intel is to the right of the body sitting inside.

30. In the room with a balcony (out on the balcony is a missile launcher), go to your left as you enter the room, and enter the door straight ahead (near the portrait of Franklin Pierce) to find the Intel on a table down a small hallway.

Act III: Contingency

31. When you reach the three-man patrol standing near the fence, kill them, and go over to where they were. The Intel is about ten feet south on a crate.

32. The building labeled "33" along the angled south-west fence contains the Intel on a metal desk inside the northern door.

33. Just north of building "33", locate the stairs leading to a helipad (has blue lights on the corners) to find the Intel in the north-west corner.

Act III: Whiskey Hotel

34. When you are told to go left to the building, inside that building after the next door has been opened, the Intel is in the hallway on a couch to the left.

35. After you go up the first stairs towards the roof, the Intel is to your right on a desk. This should be about the time when the you see the flares get lit.

Act III: Loose Ends

36. Before entering the house, go behind it, and locate the small boat hanger along the shore. The Intel is on a crate outside of it.

37. In the locked room on the top floor of the house, the Intel is on a desk in front of the door.

38. In the nearest locked room in the basement, go into the arms room to the left. The Intel is straight across from the wall of weapons on a crate.

Act III: The Enemy of My Enemy

39. The Intel is immediately to your right when you begin the mission, in the front of the plane.

40. After you slide out of the plane hull and move across the street and up the hill, look for the plane pointing towards the road. The Intel is inside, near the cockpit.

Act III: Just Like Old Times

41. As you enter the tunnels, go left as instructed. After the patrol passes, kill the guard standing at the monitor, and go straight across to find the Intel on a crate just to the right of the cave entrance.

42. The Intel is to the left on a desk right before you go outside from the tunnels.

43. After going across the ridge, the Intel is in an alcove, on a crate.

44. The Intel is on the desk with soda cans after you breach the room, near where your ally is working on the computer.

Act III: Endgame

45. The Intel is at the beginning of the mission, before you board the vehicle.

Easy Juggernauts kills
Shoot a Juggernaut in the face with the Thumper to instantly kill it.

Easy "Armor Piercing" mission in Special Ops mode
When the mission begins, grab the Barrett .50 Cal and/or Intervention. Then, keep running up the stairs until you reach the scaffolding (there is an ammo crate below the scaffolding). You may encounter a Juggernaut near the scaffolding. If so, kill it, and then climb up the scaffolding. Go prone, and just try to keep sniping the Juggernauts straight ahead with the Barrett .50 Cal or Intervention. You can also have one player hide behind the ammo crate below the scaffolding and try to lure them towards you. Alternately, have one player die on a staircase to block the path of the Juggernauts, while the other player kills them from behind it.

 Easy "High Explosive" mission in Special Ops mode
Note: This trick requires two players. When the mission begins, run to the left, and look down the alley. If there is a Juggernaut standing there, either try to kill him or stun him so you can both enter the building on the far left through the large window. Have one player stand in front of the doorway, and die while trying to shoot at the Juggernauts. Have the other player crouch behind the table next to the large window you entered through, and simply shoot the Juggernauts as they stand near the door. They will not be able to get past the player downed in the doorway. Make sure to revive the player after killing the Juggernauts standing near the doorway so they do not bleed out. The Juggernauts usually come in waves of 1-1-2-3-3. If you get a chance, you can refill your ammo near the area you started the mission.

 Easy level boosting with riot shield
Get twelve people in a lobby, and explain how the level boosting is going to work. Next, kick six people out so there are only six in your party. Then, find a Search And Destroy game. Note: While trying to find the game, make sure the host (the person trying to find the game) temporarily has a bad connection so it will make you host the lobby and not pair you with someone else. Once you are in the lobby, you can invite the other six people to join. When all the spots are filled, you can make your connection good again and begin the match. Choose a class with the riot shield. It is recommended both players use the One Man Army perk if you have unlocked it. Once the match begins, find another player, and have them keep shooting you while you hold the riot shield to block the bullets. You will get +500 experience points every few seconds five times. Once you start only getting +100 experience points, switch classes and have the other player switch to a riot shield class. Do the same things to them until they only get +100 experience points, and then switch back. Repeat this as many times as desired. It is possible to get over 50,000 experience points per match if done correctly. Note: To keep the game going as long as possible, make sure one team plants the bomb and then the other team defuses it. 

Riot shield defense
While the riot shield is equipped to one of your classes, you can have defense from the back when you are holding your secondary weapon; thus, being able to switch the direction of defense with your riot shield. This is useful in narrow corridors and stairwells. -From: Destructor58

Hidden sniper positions in "High Rise" map
Look from the center of the map at the cranes, then to the left side of the map. Go that side"s back left corner. Find the broken scaffolding. Sprint from before the ledge, and jump to the left outside yellow vertical railing of the scaffolding. This is a hidden ladder. Climb up this railing/ladder to the top of the scaffolding. Walk to the right of the scaffolding along the ledge of the building. You will eventually reach another scaffolding. Climb onto this scaffolding. Walk to the top. Look towards the building, and climb onto the higher ledge. Follow that ledge going left. Keep moving forward to reach the roof. This is a very good sniper spot. It is recommended you use a Tactical Insertion because other players may discover you on your way to the top, or while you are up there, and try to kill you. There are also a lot of teddy bears on the roof. 

Hidden Juggernaut message
Play a level where a Juggernaut can be found in Spec Ops mode. After killing a Juggernaut, look at his crotch area to see the message "Get sum!". Alternately, have yourself or a partner walk up to him, and enter last stand mode (bleed out). Then, look at his crotch area.

X-Men: Last Stand reference
The "I"m the Juggernaut..." trophy is a reference to the X-Men: Last Stand movie, where the Juggernaut is trapped in the floor and yells "I"m the Juggernaut!".

Various game references
On the Estate map, go inside the estate (the largest house in the center of the area). Use a sniper rifle, and look on the rack under the LCD television in the main hall. There is a Gamestation 5 console (reference to the PlayStation) with games named "Italian Plumber Princess Rescue" (a reference to the Mario games) and "Deer Hunter 17" (a reference to the large quantity of Deer Hunter games). Go to the basement using the stairs in the kitchen. Look at the posters on the wall around the pool table. There is one with the name "Massey Effect" (a reference to Mass Effect), and in the same poster, there is a description "Chaos Theory was just the beginning" (a reference to Splinter Cell: Chaos Theory, which is the story considered to be the beginning of the subsequent Splinter Cell games" stories).

Easy "Colonel Sanderson" trophy

Easy "Downed but Not Out" trophy

Easy "Drive By" trophy
Play the "Race" mission in Special Ops mode on Solo Play. Just keep shooting enemies on snowmobiles while driving to get the "Drive By" trophy.
 

Easy "Ghost" trophy

Easy "Knock-knock" trophy

Easy "Look Ma Two Hands" trophy

Easy "Pit Boss" trophy

Trophies
Successfully complete one of the following tasks to get a trophy:

Back in the Saddle (Bronze): Help train the local militia.
Danger Close (Bronze): Get hand picked for Shepherd"s elite squad.
Cold Shoulder (Bronze): Infiltrate the snowy mountain side base.
Tag "em and bag "em (Bronze): Find Roajs in the Favelas.
Royale with Cheese (Bronze): Defend Burger Town.
Soap on a Rope (Bronze): Storm the gulag.
Desperate Times (Bronze): Execute the plan to help the Americans.
Whiskey Hotel (Bronze): Take back Whiskey Hotel.
The Pawn (Bronze): Assault Makarov"s safe house.
Out of the Frying Pan... (Bronze): Complete the mission in the airplane graveyard.
Pit Boss (Bronze): Run The Pit in "S.S.D.D." and finish with a final time under 30 seconds.
Ghost (Bronze): Plant the C4 in "Cliffhanger" without alerting or injuring anyone in the blizzard.
Colonel Sanderson (Bronze): Kill 7 chickens in under 10 seconds in "The Hornet"s Nest".
Gold Star (Bronze): Earn 1 star in Special Ops.
Hotel Bravo (Bronze): Earn 4 stars in Special Ops.
Charlie On Our Six (Bronze): Earn 8 stars in Special Ops.
It Goes to Eleven (Bronze): Earn at least 1 star in 11 different Special Op missions.
Operational Asset (Bronze): Earn all 3 stars in at least 5 different Special Op missions.
Blackjack (Bronze): Earn 21 stars in Special Ops.
Honor Roll (Bronze): Earn at least 1 star in each Special Op mission.
Downed but Not Out (Bronze): Kill 4 enemies in a row while downed in Special Ops.
I"m the Juggernaut... (Bronze): Kill a Juggernaut in Special Ops.
Ten plus foot-mobiles (Bronze): Kill at least 10 enemies with one Predator missile in Single Player or Special Ops.
Unnecessary Roughness (Bronze): Use a riot shield to beat down an enemy in Single Player or Special Ops.
Knock-knock (Bronze): Kill 4 enemies with 4 shots during a slow-mo breach in Single Player or Special Ops.
Some Like it Hot (Bronze): Kill 6 enemies in a row using a thermal weapon in Single Player or Special Ops.
Two Birds with One Stone (Bronze): Kill 2 enemies with a single bullet in Single Player or Special Ops.
The Road Less Traveled (Bronze): Collect 22 enemy intel items.
Leave No Stone Unturned (Bronze): Collect 45 enemy intel items.
Drive By (Bronze): Kill 20 enemies in a row while driving a vehicle in Single Player or Special Ops.
The Harder They Fall (Bronze): Kill 2 rappelling enemies in a row before they land on their feet in Single Player or Special ops.
Desperado (Bronze): Kill 5 enemies in a row using 5 different weapons or attachments in Single Player or Special Ops.
Look Ma Two Hands (Bronze): Kill 10 enemies in a row using akimbo weapons in Single Player or Special Ops.
No Rest For the Wary (Bronze): Knife and enemy without him ever knowing you were there in Single Player or Special ops.
Three-some (Bronze): Kill at least 3 enemies with a single shot from a grenade launcher in Single Player or Special Ops.
For the Record (Silver): Complete the Single Player campaign on any difficulty.
First Day of School (Silver): Complete "S.S.D.D" and "Team Player" on Veteran Difficulty.
Black Diamond (Silver): Complete "Cliffhanger" on Veteran Difficulty.
Turistas (Silver): Complete "Takedown" and "The Hornet"s Nest" on Veteran Difficulty.
Red Dawn (Silver): Complete "Wolverines!" and "Exodus" on Veteran Difficulty.
Prisoner #627 (Silver): Complete "The Only Easy Day...Was Yesterday" and "The Gulag" on Veteran Difficulty.
Ends Justify the Means (Silver): Complete "Contingency" on Veteran Difficulty.
Homecoming (Silver): Compelte "Of Their Own Accord", "Second Sun", and "Whiskey Hotel" on Veteran Difficulty.
Queen Takes Rook (Silver): Complete "Loose Ends" and "The Enemy of My Enemy" on Veteran Difficulty.
Off the Grid (Silver): Complete "Just Like Old Times" and "Endgame" on Veteran Difficulty.
Operative (Silver): Earn all 3 stars in at least 10 different Special Op missions.
Specialist (Silver): Earn 30 stars in Special Ops.
Professional (Silver): Earn all 3 stars in at least 15 different Special Op missions.
The Price of War (Gold): Complete the Single Player campaign on Hardened or Veteran Difficulty.
Star 69 (Gold): Earn 69 stars in Special Ops.
Platinum Trophy (Platinum): Earn all other trophies.