Call of Duty Modern Warfare 2

Intel walk thru
http://www.xbox360achievements.org/forum/showthread.php?t=187066

Act I
Level: S.S.D.D.

Under the watch tower, straight across from the entrance to the obstacle course.

Level: Team Player

In a classroom. Someone announces "I think I saw one go in that classroom" and then your team goes in. It's on the right wall as you enter, on a desk by the barrels.
Right as you exit the school, it's on a crate directly outside, next to a taxi.

Level: Cliffhanger

Directly in front of you when you when Soap tells you to go ahead alone, there's a guard tower. Up the ladder, on the catwalk is the Intel.
When you're 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 and grab the Intel sitting inside.
During the snowmobile sequence, when you get near 1850m from the finish, stop. Somewhere in front of you you should see a small wooden fence surrounding some trees in the middle of the path, and a small wooden building up a hill to the right. The Intel is on the ground inside the fenced area with trees. Big thanks to Janco and gurnard for helping find this last Intel. [Pictures (Thanks mistical): 1 - 2 - 3]

Level: Takedown

On the map (Hit start), 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's a building with an angled wall and a large window in said wall. Go through the door to the right of that window, the Intel is straight inside. [Pic of map], this is where the motorcycle is, the building is right where I'm looking to.]
When you come up 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 right inside. [Pic of map]
Hard to describe. Inside a building you enter by going up a small wooden staircase. There's three guys inside you have to kill. [Pic of map]
Near the end of the chase, off an alley, go in the building on the right side of the path, go downstairs and the Intel is between two beds. [Pic of map]
Act II
Level: Wolverines!

On the counter in the gas station after you come through the alley.
Inside CRB Financial (Across from the Nate's Restaurant), near the front door, under a sign labeled "Online Banking."
On a table inside Taco To Go. Enter the building through the blown up corner.
Inside a dumpster (In a small brick enclosure) on the east side of Burger Town, visible from the Burger Town roof ladder. Thanks to PasPer2 for this location. [Pictures (Thanks mistical): 1 - 2]

Level: The Hornet's Nest

Near the beginning, after you move forward from the first building, go into the house to the right of where Soap stops in the road (There's a blue car in the garage). Go past the blue car into the kitchen to find the Intel on the table.
After clearing the small lot (Has a bunch of appliances and cars and whatnot), instead of going right up the stairs between buildings, go left around the three-level house (Floors are colored red, yellow, red), and look in the little hut attached to its side to find the Intel on some barrels.
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, there is an Intel laptop up on the second floor, on the table.
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.

Level: Exodus

In the apartment office, near where the enemies are first repelling in from a chopper. It has red walls and blue curtains inside. On the desk is the Intel laptop.
In the right-side building of the structure that forms an arch over the road (Has toll booths and whatnot), on a desk directly to the right as you enter.
After you cross the bridge, proceed into the second house on the right side of the street. Enter from the front door, and go to your right and up the stairs. Above those stairs is a yellow couch with the Intel on it.

Level: The Only Easy Day... Was Yesterday

In the room before you go back outside (Shortly after breaching), the Intel is on one of the metal racks against the wall.
After executing 'Plan B,' in the room Soap goes into on the right, the Intel is on a metal rack right inside the door.
After clearing outside, when the team starts going up the stairs, go in the room to the right (You were probably in this building before when told to take cover a minute ago), and look under the stairs on some wooden palettes to find the Intel.

Level: The Gulag

As your team moves towards the arch with the red light, go to the stone stairs before it, inside the room on the far wall is the Intel sitting on some filing cabinets.
On a desk behind the large wall of monitors you encounter on your way through.
After you obtain the riot shield and leave the room where you got it, turn left and proceed down the hallway. In the first open cell on the right-side wall is the Intel on a desk.
When you find the person you're looking for, turn to your left and the Intel is on the desk.

Level: Of Their Own Accord

Inside the elevator that keeps trying to close (In the hallway after you enter the building), to the right of the body sitting inside.
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) and the Intel is on a table down a small hallway.
Act III
Level: Contingency

When you come to 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.
The building labeled "33" along the angled south-west fence houses an Intel item on a metal desk right inside the northern door.
Just north of building 33, find the stairs leading to a helipad (Helipad has blue lights on the corners), the Intel is in the north-western corner.

Level: Whiskey Hotel

When you're 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.
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.

Level: Loose Ends

Before entering the house, go out behind it and find the small boat hanger along the shore. The Intel is on a crate outside of it.
In the locked room on the top floor of the house, on a desk straight in front of the door.
In the nearest locked room in the basement, go into the arms room to the left, straight across from the wall of weapons on a crate.

Level: The Enemy of My Enemy

Immediately to your right when you start the level, in the front of the plane.
After you slide down 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.

Level: Just Like Old Times

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.
To the left on a desk right before you go outside from the tunnels.
After coming across the ridge, in an alcove, on a crate. [Pic of map]
On the desk with soda cans after you breach the room, near where your ally is working on the computer.

Level: Endgame

Right at the start, before you board the vehicle.

Back in the Saddle 15
Help train the local militia.
This is a story related achievement, which will unlock with natural progression through the game.
Danger Close 15
Get hand picked for Shepherd's elite squad.
This is a story related achievement, which will unlock with natural progression through the game.
Cold Shoulder 15
Infiltrate the snowy mountain side base.
This is a story related achievement, which will unlock with natural progression through the game.
Tag 'em and bag 'em 15
Find Rojas in the Favelas.
This is a story related achievement, which will unlock with natural progression through the game.
Royale with Cheese 15
Defend Burger Town.
This is a story related achievement, which will unlock with natural progression through the game.
Soap on a Rope 15
Storm the gulag.
This is a story related achievement, which will unlock with natural progression through the game.
Desperate Times 15
Execute the plan to help the Americans.
This is a story related achievement, which will unlock with natural progression through the game.
Whiskey Hotel 15
Take back Whiskey Hotel.
This is a story related achievement, which will unlock with natural progression through the game.
The Pawn 15
Assault Makarov's safe house.
This is a story related achievement, which will unlock with natural progression through the game.
Out of the Frying Pan… 15
Complete the mission in the airplane graveyard.
This is a story related achievement, which will unlock with natural progression through the game.
For the Record 35
Complete the Single Player campaign on any difficulty.
There are a total of 18 missions in the game. Complete them all and the achievement is yours. I personally played the game in my first play through on veteran and passed the game in a day. Just keep in mind that you can't kill civilians and that there aren't any infinite respawns. Take it slow and you will pass the missions.
The Price of War 90
Complete the single player campaign on Hardened or Veteran Difficulty.
Complete the game on Veteran. This is EXTREMELY easy in comparison to Call Of Duty 4. You can get shot many times and still live but do NOT get cornered. Being cornered will mean your instant death. Take it slow and reload often. Pick up enemy weapons for ammunition and remember: Stealth missions aren't meant for you to be detected. If they find you, it will be a LOT harder. Try to flank your enemies and watch your back, team mates are horrible at protecting you. You need to stay in cover, but rememeber that wooden covers aren't the best because enemies can shoot right through it. Watch out for shotguns as the enemies has many of them and will ambush you. STAY IN COVER, this isn't Call Of Duty 5 with infinite grenades. The enemies only throw one or two grenades at most. Helicopters CAN BE KILLED WITH NORMAL GUNS! It only takes half or so of a LMG and a couple of clips of a normal gun.
First Day of School 25
Complete 'S.S.D.D' and 'Team Player' on Veteran Difficulty.
These are the first two missions of the game. Not really hard, but you have to keep in mind that once your Humvee is down, you need to get into a building to your right. Take the school slowly and do NOT try to knife the guys with RPDs that appear to not know you're there. If you get too close to them, they will turn around and kill you immediately.
Black Diamond 25
Complete 'Cliffhanger' on Veteran Difficulty.
This is the third mission of the game. Just sneak and follow Soap's instructions. After he's been compromised, you need to fight and stay in cover. Once you go down the hill, run to the shack and kill the enemies in cover.
Turistas 25
Complete 'Takedown' and 'The Hornet's Nest' on Veteran Difficulty.
These are missions five and seven. These are hard because they are VERY small, filled with enemies, and there are many places where enemies can ambush you.

Takedown: This is a small map with many enemies and many civilians. Take it slow, I mean, VERY SLOW. DO NOT SHOOT unless you know it is a bad guy. After you pass the gate with the dog, take it slower. There is VERY little space to move and many places where you can get ambushed. This was one of the hardest parts of the game, just go into a building, kill the enemies and move on. There are no infinite respawns.

Hornet's Nest: You really have to slow down. To pass the gate, run to cover and kill the enemies, eventually a Technical will come and break the game. The market is small and filled with enemies with shotguns, so take it very slow and kill the enemies. When you miss the jump, run fast as the enemies will be after you and you have about a minute to reach the chopper. Don't worry about killing anyone, just keep sprinting.
Red Dawn 25
Complete 'Wolverines!' and 'Exodus' on Veteran Difficulty.
Wolverines!: This is a long mission, take it slow and clear the streets and eventually you will end up in the small complex of fast food restaurants. Here, you can get the 10 kills with predator missiles. All you need to do is kill all the enemies and hold out, protecting the VIP. You will be informed of enemies entering from X direction, so switch to the predator missile and fire away.

Exodus: This mission is building to building combat, but you have a Striker. Use the laser designator for the Striker to kill enemies. WATCH OUT FOR THE STRIKER! IT CAN KILL YOU! I cannot tell you how many times I've been run over. Once you cross the bridge, take it very slow. Use the striker to clear the outside of buildings. Move up slowly because there are A LOT of enemies. Once you reach the mansion, clear it from the basement up, slowly watching the corners. Once done, use the laser on the AAs and then head to the last house. There are only two or so enemies at the end of the mission.
Prisoner #627 25
Complete 'The Only Easy Day... Was Yesterday' and 'The Gulag' on Veteran Difficulty.
The Only Easy Day...Was Yesterday: Make sure you watch your fire because there are many explosive barrels with C4 and many civilians. Take it slow and kill the enemies. When you do a breach, make sure you're hitting enemies and not civilians. At the end of the mission, you will need a thermal scope and enemies have them as well so stay in cover. Once all the enemies are dead, proceed to the last breach.

The Gulag: You start off with sniper fire from the helicopter and later you will land in the facility. Go inside, pick up some weapons and get ready for close quarters combat in the facility. As you progress through the mission, you will reach a part where Ghost says: There is a bathroom through this wall, you will plant a breach charge. Breach in, use the grenade launcher in the back and knife the others. You can try and fight, but I just used flash bangs and ran in. Once you drop down the hole in the final room you beat the mission, even if you didn't kill one enemy.
Ends Justify the Means 25
Complete 'Contingency' on Veteran Difficulty
Follow your leader and snipe/sneak into the facility. Once you regroup, use the Predator Missile and eliminate the enemies. Once you're done, you will enter the main facility and you have about two minutes to reach the sub. Use the Predator Missile on the Helicopter/tank and kill the enemies, rush to the right and get out at the fence. Kill the enemy near the garbage and use another predator missile at the vehicles. If you do this quickly enough, you get a check point. Use the predator missile to clear the enemies after this and run towards the sub. Once there, kill the enemies and climb the ladder with your team mates and use the predator missile at the enemy vehicles.
Homecoming 25
Complete 'Of Their Own Accord', 'Second Sun', and 'Whiskey Hotel' on Veteran Difficulty.
Of Their Own Accord: Follow the SGT into the building and clear it out. As you proceed through the rooms and floors, you will reach a room without walls, with snipers and rockets and enemies. Kill the enemies and use the Barret. Kill the RPG soldiers and pick up the javelin. Destroy the tanks and watch out for the choppers, they know you're there. After that, kill the enemies entering the building and head to the roof for extraction. Use the Machine Gun to kill infantry and defend the chopper.

Whiskey Hotel: Move through the tunnels and prepare to fight for the Whiskey Hotel. Don't try and rush, just wait for your team mate to say: Ramirez, move left, or squad move to cover. Move towards the downed chopper and then enter the West Side of the building. The following is close quarters combat and you won't have ACOG sights or Red Dots working, so take it slow and move forward. After killing a few enemies, you will have two to reach the roof but there isn't actually a timer. The time goes down as you get to certain points on the way up to the roof.
Queen takes Rook 25
Complete 'Loose Ends' and 'The Enemy of My Enemy' on Veteran Difficulty.
Loose Ends: The only hard part is the last part, where you have to escape. Once the download is done, exit the building killing the three or four enemies inside. Get to cover, kill any enemies near you, and run towards Ghost. Once you are ambushed, throw all the flash bangs and flank them, once they are dead run towards the objective.

The Enemy of My Enemy: This is one of the harder missions but you can make it easy if you don't fight anyone. The two groups will be fighting each other and they won't focus on you unless you run out in the middle or you shoot someone. Try to just sneak through the planes without firing unless someone is looking directly at you. Be careful when you are about to drop down out of the plane. Try to kill everyone you see before you drop down.
Off the Grid 25
Complete 'Just Like Old Times' and 'Endgame' on Veteran Difficulty.
These are the last two missions of the game.
Just Like Old Times: Just follow your leader and only kill when he tells you to. Once you make it to the steam room, flank the enemies and follow the lead. In the next room, flank the next enemies and get ready for a Breach. Breach, watch your fire, there are explosives in this room. Now, activate the console and get out. Kill the enemies outside, and move on to the cave.

End Game: Drive the boat and only focus on that. Shoot only if necessary.
Pit Boss 10
Run The Pit in 'S.S.D.D' and finish with a final time under 30 seconds.
Finish the Pit in the first mission. I took a Scar with an MP-5. There are a total of 24 enemies and you have thirty seconds to kill them, without killing a civilian. Run up, kill the first three guys, then kill the next three, and then the next four. Enter the room, kill the three guys, go up, knife, kill the next three and jump. By now, you should be out of Scar ammo so switch to MP-5 (do this before jumping), kill the last enemies and DO NOT hit a civilian! It's really easy at this part since the bullets pass through the enemies. Finally, sprint to the finish. You get a time deduction for accuracy and no civilians hit, so just keep running the course until you get it.

Here's a video:






Just remember: He took his time, but he didn't miss a shot. You have to be accurate in order to have a time deduction, in his case, he took about 35 seconds, but because of his accuracy, his final time was 29 seconds.

Ghost 10
Plant the C4 in 'Cliffhanger' without alerting or injuring anyone in the blizzard.
This can be done in any difficulty. After you climb the ice and kill both sets of enemies, you and Soap will separate and a blizzard will appear. Take out the gun with the heartbeat sensor and crouch towards the objective. Do not kill or injure anyone and make sure you aren't caught. If you are caught, you can restart from the last check point. Wait for the guard near the objective to move near the car and pass next to him. Do not go inside the building. Move towards the other building on your left, and head towards the edge of it (near the small hill). Soap should mention something about a car but just keep going. There should be one or two dots in your sensor but they can't see you. Ignore Soap when he says there are enemies on the runway, just keep going and plant the C4.
Another way to do this is to follow this video by Mistical:

Colonel Sanderson 10
Kill 7 chickens in under 10 seconds in 'The Hornet's Nest'.
This can be done in any difficulty. Play Hornet's Nest, and when you reach the Market, kill all of the enemies. DO NOT harm any chickens. Once everyone is dead, find a small group of six or so chickens on the left side. Throw a grenade and shoot another four. While in the market, you might get this randomly, but it is best if you clear the market first and then kill the chickens.

Gold Star 20
Earn 1 star in Special Ops.
Spec Ops are missions where you have to do different tasks. There are 23 missions with a possible 69 stars. You get one star if you beat the mission on Regular, two for Hardened, and three for Veteran. Some missions are hard, some are easy. For this achievement, just complete the first Special Ops mission, The Pit, as fast as possible. Be as accurate as possible as well, you get three stars if you do it under 35 seconds.
Hotel Bravo 20
Earn 4 stars in Special Ops.
Refer to Star 69.
Charlie On Our Six 20
Earn 8 stars in Special Ops.
Refer to Star 69.
It Goes to Eleven 20
Earn at least 1 star in 11 different Special Op missions.
Refer to Star 69.
The easiest missions are the Alpha and Bravo missions. Once you finished all of those, just complete the Time Trial in the Charlie section to beat 11 missions.
Operational Asset 20
Earn all 3 stars in at least 5 different Special Op missions.
Refer to Star 69.
The easiest missions are in the Alpha section. Just complete all of them on Veteran to get 3 stars in each.
Blackjack 20
Earn 21 stars in Special Ops.
Refer to Star 69.
Honor Roll 20
Earn at least 1 star in each Special Op mission.
Refer to Star 69.
Operative 30
Earn all 3 stars in at least 10 different Special Op missions.
Refer to Star 69.
The easiest missions are in the Alpha and Bravo sections. Complete all of them on Veteran to get 3 stars in each.
Specialist 30
Earn 30 stars in Special Ops.
Refer to Star 69.
Professional 30
Earn all 3 stars in at least 15 different Special Op missions.
Refer to Star 69.
Star 69 90
Earn 69 stars in Special Ops.
This is the hardest achievement in the game. You will need to pass all 23 Special Ops missions con Veteran. Two missions require you complete with a partner, but the other 21 missions can be completed alone. It is recommended that you have a teammate because instead of dying right away, you will get downed and be able to get revived. If you try the missions by yourself, you won't get downed and you die right away. Take them slow, only seven missions are timed.

Refer to this thread for good strategies for all of the Special Ops missions.
Downed but Not Out 10
Kill 4 enemies in a row while downed in Special Ops.
You need to play co-op Special Ops for this. You can do this either with another player over Xbox Live or just with a second controller. Once you're downed, you're in last stand with your pistol. Kill four enemies, but if you get shot again then you can only crawl and do nothing else. Another shot and you're dead.

The easiest place to get this is on the second Special Operations mission, Sniper Fi. A few seconds after you start, you will be able to pick up the predator missile launcher. Once you pick it up, open it by pressing but don't fire it. Wait for a lot of enemies to be right next to each other. Once they are, shoot the missile by pressing . Move the missile towards the enemies and when it is lined up, have the second player knife you by clicking the . This will down you and while you are downed, the predator missile will kill the enemies, giving you the achievement.
I'm the Juggernaut… 10
Kill a Juggernaut in Special Ops.
Only explosives and high caliber bullets can kill Juggernauts. They appear only in Spec Ops in Snatch and Grab, Estate Takedown, High Explosive, and Armor Piercing.

The first Special Ops mission you can get this on is Snatch and Grab. You can play on Regular to make this easier. When you first start, you will have the Intervention as your secondary weapon. Switch to this weapon () and then wait for a Juggernaut to appear. There should be a one at the start of the mission but if not, you can either progress through as normal or restart it. Once you see one, shoot it five times and you should kill it. You can also use 4 RPG rockets to kill it or a full LMG clip.
Ten plus foot-mobiles 10
Kill at least 10 enemies with one Predator missile in Single Player or Special Ops.
The easiest place to get this on is the mission Wolverines! in the campaign. Towards the end of the mission, you will get attacked by multiple large groups of enemies. Each group has more than 10. Once the first group attacks, pull out the Predator missile with and then shoot it with . Move the missle into the middle of the group of enemies and you should kill at least 10. If you don't, you can just wait for the next group and try again.
Unnecessary Roughness 10
Use a riot shield to beat down an enemy in Single Player or Special Ops.
An easy place to get this is on the mission The Gulag in the campaign. Towards the middle of the mission, you are forced to pick up a riot shield. Crouch to make sure you won't get shot and then walk towards an enemy. Once you are close, click the to beat them down. It only takes one hit to kill them.

You can also pick a riot shield up and kill an enemy in No Russian (the optional mission in the campaign) and then Special Ops missions Breach and Clear and Terminal.
Knock-knock 10
Kill 4 enemies with 4 shots during a slow-mo breach in Single Player or Special Ops.
A slow-mo breach is when you breach into a room with the wall explosive. The best way to get this achievement is to play Special Ops mission called Breach and Clear. Switch to your M203 grenade launcher by pressing and breach the wall. Once you are in slow mo, fire a at the group of people that is a directly in front of you down the hall.
You can also follow this video by Mistical:

Some Like it Hot 10
Kill 6 enemies in a row using a thermal weapon in Single Player or Special Ops.
A good place to get this on is in the mission The Only Easy Day... Was Yesterday in the campaign. Once you get to the top floor, you will be told to use thermal sights. Pick up a weapon from one of the boxes on the floor right in front of you. When you zoom in, you will be able to see enemies even through smoke, they will be all white. All you have to do is kill 6 in a row.
Two Birds with One Stone 10
Kill 2 enemies with a single bullet in Single Player or Special Ops.
You should get this playing normally, but if you can't, play Spec Ops mission called Hidden. Kill the first enemy with the pistol and move forward. There are two enemies speaking with one another, line up the shot and kill them. There are other places within this mission to do this, so don't worry if you miss. When you reach the church, climb the tower and kill the two soldiers speaking in the building opposite of you.

Here's a video by Subwayer done on Spec Ops Hidden:

The Road Less Traveled 10
Collect 22 enemy intel items.
Refer to Leave No Stone Unturned.
Leave No Stone Unturned 10
Collect 45 enemy intel items.
You can find the intel on any difficulty and the ones you found will carry over to any playthrough. You can also just pick up the intel and quit the mission.

Look HERE for an intel location guide.
Alternatively, you can watch these youtube videos:

and:
Big thanks to Tural for the written guide and Mistical for the videos.

Drive By 10
Kill 20 enemies in a row while driving a vehicle in Single Player or Special Ops.
The best place to get this is the final mission of the campaign, End Game. You drive the boat with and you can shoot enemies with Just shoot whenever there is another boat in front of you and when you pass the enemies on the side of the river.

You can also get this at the end of Cliffhanger but End Game has a lot more enemies that you can kill.
The Harder They Fall 10
Kill 2 rappelling enemies in a row before they land on their feet in Single Player or Special Ops.
You can get this in campaign, in missions like Whiskey Hotel or The Only Easy Day... Was Yesterday, but you can do it in Spec Ops mission called Suspension in Alpha. Take a few steps, and from both sides of the bridge there will be a squad descending. Kill two of them, and achievement unlocked. Here's a video by Mistical:


Another good mission to get this on is the Special Ops mission Overwatch. If you are the player in the AC-130, you can shoot down enemy helicopters easily with the 40 mm weapon. When you see an enemy helicopter, wait until there are a couple enemies dropping out of it. Once you see them, shoot the helicopter down. All of the rappelling enemies will drop down and die and you will get the achievement.

Desperado 10
Kill 5 enemies in a row using 5 different weapons or attachments in Single Player or Special Ops.
You can get this on any campaign or Special Ops mission. The best places to get it are missions where you start off with a weapon that has either a grenade launcher or shotgun attachment. First, just kill an enemy with your primary weapon. Then kill an enemy with your grenade launcher or shotgun attachment. Then switch to your secondary weapon and kill another enemy. Then pick up another weapon off the ground and kill another enemy and then do the same thing with another gun you picked up off the ground get the achievement.

Some people have been able to use their knife as one of the weapons but others have used it and have not unlocked the achievement. If you use the knife and don't unlock the achievement, just pick up another weapon from the ground instead.

Look Ma Two Hands 10
Kill 10 enemies in a row using akimbo weapons in Single Player or Special Ops.
Akimbo weapons are dual wield weapons. You can use either double G18s, Uzis, TMPs, etc. I got this in Loose Ends with dual TMPs, but you can get this on Bomb Squad in Bravo Spec ops. You start off with dual G18s so just kill ten enemies. You can't aim down with akimbo weapons so that makes it slightly harder than normal weapons. You use and to shoot.
No Rest For the Wary 10
Knife an enemy without him ever knowing you were there in Single Player or Special Ops.
The easiest place to get this is in the Cliffhanger mission in the campaign. When you are told to go plant the C4 by yourself, you will probably come across an enemy that is in a house sleeping. Just walk up behind him and knife him. The location of this enemy is in this video made by Mistical:

Three-some 10
Kill at least 3 enemies with a single shot from a grenade launcher in Single Player or Special Ops.
Refer to Knock-knock

https://www.youtube.com/watch?v=QJAbCuwcWxo