Get ready fellow soldier for these tense missions ahead, you are required to complete all off these tasks with stealth, speed and most off all "stay alive", yourself and your fellow grunt are needed on the front line to finish six cooperative missions, each off which have there own unique way off achieving total success as listed below, follow these orders and you will make it out alive, failer is not an option, so, saddle up, lock n load and get ready for your mission brief...
There are six mission in the co-op section off Battlefield 3, each mission can be played in three different levels,  Easy  Normal  Hard. You can play the first two, but too carry out mission three you must successfully complete the first two, this will open up the next and so on. If this is your first time playing the co-op section off Battlefield 3, start by trying it in 'easy' mode, when each mission ends your scores will appear on your screen.
This tutorial is mainly for Xbox 360 players' but, too my knowledge, it's has the same approach and mission objectives in general for the PlayStation 3, the main controls on the control pad are all different ofcourse (Xbox controls on the left) X=Square : A=X : Y=Triangle : B=Circle
 Operation Exodus
 Fire From The Sky
 Hit And Run
 Drop Em Like Liquid
 The Eleventh Hour
Before you start it's benifical too play these missions when both players are using a mic's, otherwise it maybe slightly harder to finish them successfully, agreed, the first mission can be done by both players' without a mic, but the rest do require two mic'd up marine's.
Mission Objectives: Complete the mission without losing a humvee.
There are no more than three waves off enemies that will attack you from many different angles and areas, your fellow grunt as do the marines you notice whom are on the ground as you make your way to your location which will be marked with a blue square on your screen. At the beginning off the mission, make your way along the sidewalk, turn left, you will notice an overpass about 50 meters in front off you, to the left off the steps you will notice an ammo stash, take a look at what weapons, rockets etc it has to offer you. It would be a good idea if both off you begin to make your way up the steps to the overpass, this is benifical as it gives you a birds-eye-view off the battlefield, plus, if one off you just happen to be shot and are down your fellow marine can revive you reasonably quickly then both can return to the fight.
The first wave of enemies will come down the main avenue where the overpass looks over, simular to the campaign mode in Operation Swordbreaker. Unless you're fine with going prone and using an LMG's bipod, it may be to your advantage to stick with either an M4 Carbine (with some type off scope) or the reliable M39 DMR, or which ever weapon that you are comfortable with, there are no rules to which weapon you must use. It would be beneficial to use the bulk of the staircases as cover and keep back the wave off enemies. Once you have elimated a number off PLR the dreaded BMP will appear at the top off the road, it's very visible not to mention very dangerous, (it's the orange target marker on your HUD/Screen) rumbling down the street.
Provided you've taken out most (if not all) of the enemy infantry in your immediate area, you should have a clear line of sight to fire your Javelin weapon (it will occupy your second weapon slot) switch too it as soon as you are safe to do so. Also, remember to restock up on ammo, rockets, mines etc at the ammo crate at the bottom off the steps. Remember that Javelins are top attack missiles, which means you fire over the top facing of an enemy armour unit so the missile can arc down. the top and bottom off armour is generally weaker than the front or side. Three good strike's from your Javelin should distroy the BMP (all difficulties). Don't forget to achieve a single, solid tone for lock-on before firing your big gun!!! Do not let your fellow marine die, if he does it's "game over" stay close together, communicate as much as possible.
This second wave of enemies starts off attacking from the left corner where the massive pile of ammunition and weapons are. They are both high and low, the enemies will pop out and attempt to overwhelm you from these areas. Those anti personnel claymore mines will be handy, but you can make a fairly solid last stand by using the massive bulk of the ammunition replenishment point to shield you from bullets while you pick away the enemies. The real danger comes from the second wave's BMP, which pretty much pops out from the alley adjacent to the ammunition pile. If you are situated next to the ammunition boxes when this occurs, you have maybe two, perhaps three seconds to aim, lock-on and fire on the enemy armour unit. What you want to do to prepare for this eventuality is to stock up on ammunition and crawl, make way to either the pedestrian overpass or a spot which give you excellent cover between you and the dreaded BMP.
You can also remain on the overpass taking out the foes which are in the upper floor in the building to your right (beside alleyway), this might be a good idea, simply when the BMP arrives you have a good spot to use your Javelin. Alternately, you can place AT mines near the ammunition crate or in the alleyway if you chose this method be "quick". One of the problems with this tactic is that you have to do this before the armour unit appears (meaning enemy soldiers have free reign to kill you while you lay mines), and the fact that the BMP does not travel on a track and can evade the mines (this is a random occurence) or place the mines on the road directly under the overpass, but if you choose to do so do this as soon as you arrive at the ammo crate before battle begins. It's best to take down the second BMP with your trusted Javenlin from a distance, instead of relying on old-fashioned static AT mines, use the old tactic of "hit-and-run" to elimanate all foes in this second wave.
This final wave of enemies will attack from the intersection behind the pedestrian overpass. This means you will have to leave your current location and make your way over to the street behind you. Just as a point off interest, you will find a second ammo crate loaded with bullets and bombs in a small building at the intersection. This "ammo building" has a replenishment station inside, as well as a second set of ammo boxes on its rooftop. To reach the rooftop, just use the ladder on the building's side. The rooftop is highly exposed, but it offers the best vantage point to take out those enemies in the tenement building across from you. The fields of fire from the lower room are limited, and very dark. The enemy BMP will appear from the tenement building (bursting through its front door) and immediately tries to attack the friendly HMV's which you need to protect, keep these HMV's protected at all costs.
Try and destroy the enemy BMP before too many of your own HMV's are destroyed, the more .50 Caliber BMG's you have firing from your convoy the better, as you will need their covering fire to suppress enemies as you commit to a strategic action (to the extraction Osprey back at the intersection) This third wave is all about taking out as many off foes that both off you can until your air lift arrives to take you back to base for de-briefing before your next mission, use the ammo crate on the roof to stock up on munitions etc, and start throwing hand grenades at the enemies hiding behind cars and vans also, you might want to use your snipers rifle to take down the foes on the buildings in the distance.
[Tip] Try not to lose any off your HMV's during the whole mission, if you manage to achieve this you will be rewarded in kind, can't say what the reward is it will only be a spoiler.
Fire From The Sky:
Mission Objectives: Protect and support three fire teams on the ground, give covering fire at all times, elimate all danger's. Do not let your "High Valued Target" die.
[NOTE] By default the host is normaly the pilot, but after a few crash each player will have his/her turn at being the pilot or if you use the "B" button you can normaly swap seats prior to take off. Watch your screen at the very begining off this mission, just before you take off in the helicopter, this will give inform you which buttons to use while in-flight, as it will during your mission. Most targets will appear as Orange square's on the battlefield, except for all foot soldiers.
The main role off the pilot is to keep the aircraft in the air, at times, giving some covering fire to the enemies below whom are trying to kill both your three squads and your HVT (High Valued Target). Plus, provide a reliable stable platform for your gunner to do his job quickly and with ease, this does not mean that the pilot cant not engage in a firefight, for you as the pilot have a few neat weapons in the arsenal, namely unguided rockets, so take your time when you unlease them, make every one count, consider using them at mobile AA guns, mortor emplacements and tanks etc.
Your role as the gunner will be doing most of the killing since your weapon systems are much more suited for precise targeting, and the weapon impacts have an area of effect (AOE) that makes your mission objectives that little bit easier, but, you are not restricted to what you can do whilst in he gunners seat, talk with your pilot as offend as you can, tell him where you want to go when you spot enemies on the ground, use your radar to help to watch this at all times, use terms like "enemies at our 9 O'clock" the pilot will then know to move about 90% to your left, or "Mortor team on or 12" he will know to move forward a few feet ahead towards the target(s)
As the gunner your arsenal is kool, you have a 30round (30mm) cannon, to start off with, when the firefight becomes a little fast you can switch to your anti-tank Hellfire missiles (via your Target Acquisition Designation) you can switch between the regular and TADs view. When you are in TAD's view, it has a zoom factor of about 1.5 when you use the thermal detection. Thermal detection is handy to use to help you in locating enemy foot soldiers' (infantry) if their tracer fire does not give away their position to you or your pilot before hand. Depending on the altitude off the helicopter, enemy fighters' will be difficult to see against the sparse desert terrain. Thermal detection will detect them when you are viewing a particular spot, infantry can be dispatched by the pilot (Hydra rockets) or the gunner (Cannon), decide whom is going to take these foes out, there's no reason for both off you to start firing and waisting vaulable munitions, especially rockets.
Enemy vehicles in the form of High Mobility Vehicles (HMV) and Boyevaya Mashina Pyekhotas (BMP) will enter into the operation zone. While both enemy vehicles are vulnerable to cannon fire, the BMPs can withstand considerably more hits than an HMV. Gunners may want to soften up a BMP with a Hellfire missile before finishing it off with cannon rounds. Pilots have no choice but to use repeated Hydra rocket strikes, or allow the gunner to blast away with hellfire rockets.
Enemy anti air tanks are more of a danger to you than to the NPC allies you're defending for this mission. Like the BMPs, mobile AA are marked like in Operation Exodus with the high-danger extreme threat orange HUD marker for both players. Make every effort to stand off and deliver a Hellfire missile to this armour unit before you rush it with cannon and Hydra rocket fire, or it will probably blow your aircraft out of the sky. Your mission ends when you have successfully reached the far tunnel, shortly after your rescue crew in other helicopters arrived to pick up your three teams off marines on the ground and your HVT, but stay alert anything can happen, it's not over untill it's over soldier.
[Tip] Press "X" to reload you cannon at every opportunity, be ready for your next firefight. As the pilot, don't be afraid to back off from some firefights, use altitude as a weapon to dodge incoming fire, but, at the same time protect the ground crew. If the need arise you can use your fire extinguisher to put out the fire, but, if you do not you will be rewarded in kind, say would only spoil it for you.
Mission Objectives: Infiltrate the building stealthily and extract the HVT under heavy fire. Thermal scopes are available on the default weapons. Shooting the security cameras and making stealth kills (or simultaneous double takedowns) will allow you to enter without alarms sounding resulting in your cover being blown.
Both of you will do well to use the silenced handgun's to elimate the enemy hostiles in a double takedown(s). Decide which target you and your partner will take (left or right), aim at a target and inform your fellow marine that you are ready (Ready buddy), and do a countdown (3, 2, 1) then both off you fire (aim for the head for a quick take down). You may need a few rounds to completely down an enemy if you are aiming at the body (all PLR fighters wear body armor, unlike traditional insurgents). Don't worry about ammunition, as there is more than enough bullets for this short infiltration section. Note that all enemy encounters are pre-staged, but may enjoy a small degree of randomness if you are slow to get to a certain spot.
Closed Circuit Cameras (CCTV):
There are approximately six cameras that will alert the foes whom maybe near the HVT. To get to the HVT, you will need to destroy all the cameras before they detect you, this is paramount in your main objective(s) this will enable you to fully use stealth in this part off the mission.
The first camera is right after the first two pairs of enemies. It will be in the corner just above the door you take to exit, in fact, one of your hostage takers' will make a comment about the CCTV system as you approach. A single bullet should take out all the cameras'.
This second and third cameras are in the winding hallway with the metal fencing on both sides. Check the ceiling corners at each turn, there are two cameras in this section.
Your third camera is in the winding hallway with the metal fencing on both sides, on the turn right after the second camera. Check the ceiling corners at each turn and give the leading player a lot of room to manuever in case he needs to back-up to hide or take some type off cover.
Camera's fourth and fifth are on the stairs as you make your way up to the HVT's floor. Take out the cameras and the enemy guards carefully, use stealth as much as possible, as missing them will and alert the guard resulting in the remander off the alarms going off.
The fifth camera is on the stairs as you proceed up to the HVT's floor, on the last turn before you reach the top. Take out the cameras and the enemy guards in tandem, as leaving one around when the other is destroyed will sound an alarm.
This final camera is down the hall past the HVT's room. Shoot it before approaching and breaching the hostage's door, or you will get a very nasty surprise.
Making Your Escape:
You escape the PLR pursuit by using the scoped weapon(s) to take down the enemy snipers on the rooftops. Stock up on the ammo box before moving on, and be sure to have the SVD Dragunov so you can do some long distance sniping when needed. One player will have the weapon, but the second player will need to manually take the replacement SVD by the ammo box.
Defend the HMV's at the construction yard. Take out the enemies in the building, but watch the sides, keep scanning in all directions for any unwanted surprises. If you make it to a point in the yard from the corner of the contruction crane, you will be able to see a number off enemies begin to pour into the street, make sure that both off you have enough viewing abilities too take down entrenched enemies.
Demolish The Gate:
After the gunride, C4 is needed to destroy the roadblock which can be found in the ammo crate right next to roadblock. It would be good insurance to place mines or at least cover the market stalls to the convoy's right, as enemies spawn once a player takes the C4 charges. Destroy the gate using C4 charges (deploy and detonate), and drive back to the HMV's to get out.
Hold Until Relieved:
The whole convoy will hole up in a small room opposite the plaza. Small arms fire and a group off foes will rain on your parade, if you have a full magazine and firing semi-automatically, you should be able to deal with the hostile bot-rush (AI's) until you've met your kill quota (watch out for snipers across the street). Once that's been done, start to make way to the extraction vehicle in the middle of the plaza, if all goes well as it should you have completed this mission soldier, return to base for de-briefing marine.
[Tip] Be as stealthy as both off you can be during the first part off this operation, your goal is also not to alert any enemies while conducting this mission, if you succeed in completing this task soldier without alarming anyone you will be reward.
Hit And Run:
Mission Objectives: This is a straight-forward mission with a straight-forward goal, get to the garage and escape the enemies that are using a French-built, petrol-burning motor vehicle. The related extra condition for this mission is... 'Reach the garage without going into man-down state'
You start off in a room about to be breached by enemy forces. Plant some claymores in preparation. There is a breach point that appears. When the lights go out, the breach will commence after a few seconds. It is imperative that you survive by taking cover quickly and take out anyone that is wanting too kill you our your team mate. Cover all the entrances as best you can, elimanate any enemies that are hidden in the shadows.
[HINT - You will want to keep a handy assault rifle with a Red Dot sight for the close quarters combat you will be doing. The MP7 is fine, but the small 20-round starting magazine is earnestly too small and the weapon's damage rating, too low for it to be effective but it works in most CQB's]
Now it’s time to exit. Go through the door with exit sign above it and neutralize the enemies down the hall. Watch out for grenades that will be heading in your direstion. As soon as you reach the end of the corridor, enter the door into another room full of foes. There will be an ammo crate on the left, stock up on supplies. Now, follow the marker as it leads you down the stairs. When you reach the bottom, take out the enemies on the second floor and use cover as you methodically clear the room. Keep moving forward as you’ll will be going up a set of stairs to the next marker.
When you reach the marker you’ll hit a door with an ammo stash on the left side of the room. When you’re done resupplying, enter the door. The door will be stuck. Be ready to defend yourselves. Use the desks for cover against the fire. Since it’s a bit dark, so don’t forget to mark (spot) targets for each other. After you’ve successfully defended this area, head to the previously stuck door and then take out the enemy who will be waiting as you open it.
Follow the flight of stairs down as your partner takes the floor above you. Or vice versa (chose whom is going where at this point). You’ll then both enter the room. Kill any enemies you see. Enemies will be holed up in rooms above and the left hand side if you’re on the second floor. Keep pushing forward to the marker as you and the opposing force destroy the room. When you reach the long corridor take out the enemies behind glass. When you reach the end of the hallway, open the door and run down the stairs. [HINT - One off you will prob' require assistance - it's likely that it will require a 'revive']
As you reach the bottom you will enter a small room as a buffer between you and the enemies. Luckily there is an ammo stash here you can use (resupply once again). Use the room for cover and take out the enemies in this area. When all enemies are down, move forward and run through the narrow hallway. An ammo crate will be on your right.
Finally soldier(s), enter the garage, take out the enemies along the way and enter the vehicle (don’t forget to open the gate) and drive toward the marker through the lot amidst all the gunfire. Smash through the gate at end and it’s mission over, congratulations marines, you both have completed this co-op mission, return to HQ for a de-briefing before your next cooperative mission(s).
[Tip] Use any weapons that are laying around and check them out, see what 'loadouts' they have this might work in your favour, use plenty off cover as you both make you way throught rooms, support each other and stay close when possible.
Drop 'Em Like Liquid:
Mission Objectives: Reach and save the hostages without alerting any enemies. Stealth is paramount here soldier, do not fail us, them or the mission ends.
This mission marine(s) is straight foward, both off you have to reach and save the hostages without alerting any enemies, or losing any off them, think you got want is required, following the seven simple steps should grant you total success. so, stock up on what you need, lock n load and get ready for briefing.
[Tip] It is not a bad idea to decided 'who's gonna take out who' so, it's benifical to decide who going be in charge off this mission, giving out the required orders' when there are two enemie soldiers next to each other,
 As the police lights blind you, walk through the commotion and head down the ladder into the sewer. Follow the cylindrical corridor as you pass by each marker. When you reach the end, take out the enemy in front of you (use your knife or silenced weapon), then climb up the ladder.
 You’ll appear on the surface. Two enemies will bar your progress. Kill both enemies simultaneously (with silenced weapons), then proceed. As you turn right, two more enemies will be standing inside a tunnel. Take them both out. The path with turn you left with two more enemies to simultaneously kill. Head for the marker by climbing the staircase. When you both arrive, open the door.
 Clear all the enemies inside the room. There’s an ammo crate inside one of the rooms. Now when both of you are ready, set up a position by the window and face where the “Protect” marker is. Look down the sights and a couple of enemies will be highlighted. Take them both out at the same time using your sniper rifle(s). As the squad you need to protect moves, two more enemies will be highlighted by a van. Neutralize them.
 Rescue the hostages on the bus, by first using flashbangs. The game will prompt you, just follow the onscreen instructions (as there are two buses, each decide which bus to take) You’re done in the apartment, now exit and climb down the stairs. When you reach the bottom, turn right and run down the road. Across the bridge will be two enemy positions that will appear. Take the first pair on the left, then the second pair on the right. Keep following the road down, while keeping an eye on the marker. You’ll see another group of enemies. This time three, try to take them out, but if you can’t, two more enemies will appear. Take out any enemies to proceed.
 Keep following the squad you need to protect and a sniper shot will ring out. Eventually enemies will appear. Zoom in and take them out. Keep moving forward. You’ll get attacked on your side, so take cover and kill the forces. When they’re gone, head up the steps toward the vantage point there’s an ammo crate up there and a few other items, restock on ammo etc.
 An attack marker will appear. Take out both of the enemies. Another pair will appear after the squad you’re protecting advances. Take them out as well. These guys are moving at first, so wait for them to stop. When they’re taken out, enemies will emerge from the building with markers. Wait until they stop and then give them both 'two-to-the-head'. As the team advances closer to the building, another pair of enemies will walk up behind a window, take them out quickly (do not miss or all hell breaks, possibly resulting in a mission failer).
 Finally you’ll see the team reach the hostages. Spot the bad guys to make sure they’re enemies, then press the button displayed on your screen to have them throw a flashbang. Kill the guys you marked and for good measure, take out the enemies that exit the building.
[Tip] Success is almost assurred if both marines are mic'd up any ready for action, this co-op mission requires a steady hand, you will be both using high power sniper rifles in the important part off this task, your skills will be reward if you both can complete this mission with out altering and off the enemies or those responsible for taking the hostages', also, deploy your bipod when using your sniper rifles, a quick "double-tap" to each enimeis head should take them out.
The Eleventh Hour:
Mission Objectives: Keep your HVT alive and take out as many enemies as you both can, disarm the bomb, stay in cover when the need arise, restock for many tense firefights.
Basically, this is Operation Metro with a lot of foul-smelling gas on the train platform. You venture down into the metro station and takedown enemies as they come. Unfortunitly, The gas-filled rooms and hallways are dark and make it difficult to spot enemies until they fire. You may want to buddy up and proceed carefully to the bomb. Enemies are fairly limited and stream in slowly for now.
As you put on your gas masks, jump down into the subway walkway below. Use the pillars for cover. Aim down the hall and take out any enemies that show there faces. Keep advancing toward towards the information hub, where there’s a helpful ammo crate, restock on what you need at this point. Follow the marker down the escalator.
You’ll see a stopped train on the left. Aim down the corridor and shoot any bad guys that shoot at you. The situation might get a bit dark, so mark any enemies that you can for elimating. Keep moving forward and take the room on the right and climb the escalator, then head down and take out more enemies that appear. Right before the next escalator, head into the subway car and press the required button on your screen, this will begin the process off disarming the bomb, for who ever is disarming the device, the other marine "must" keep watch as enemies will attack both off you from different angles, so keep alert soldier. Afterwards you’ll need to follow a sequence, then assit your fellow marinee finish off any remaining enemies.
When both off you have finished taking out the enemies a new marker will appear. Go up the escalator and follow it. Kill the enemies that are waiting for you on top. Push forward toward the marker as eliminate any foes along the way. When you reach the marker head out the door, into the hallway and enter another door. There’s an ammo crate here, use it now. When you enter the room, move right up the stairs and you’ll be running through the streets of Paris. Run for the marker where enemies will be shooting at police officers (stay put, do not move on at this point, patiently wait a few seconds). Make your way up the stairs and into the building. Take out the enemies in the lobby as you head for the next marker. As you move forward, kill the enemies behind the information desk.
Keep following the marker push forward once again, down the hallway, past the ammo crate and up the stairs. When you reach the blue door, open it and immediately fire upon the enemies inside the room. Make use of the ample cover as you advance. When they’re all gone, head for the marker by the pair of double doors. When you’re ready, press the button on your screen to breach. The enemies inside the room will be in for a surprise. Take out the enemies in the room. There will also be a few above you, take a good look around this area soldier.
Now to the final room marines, first off all, be well stocked up on munitions etc, move to the marker and stack up with your felloow soldier. One of you will be grabbed by the HVT. Quickly press the button shown on your screen to get him off, then the other will shoot him dead. Watch the cut-scene... Congratulations marine(s) You’ve just finished the co-op campaign for Battlefield 3. Keep playing until you unlock more items for your multiplayer experierce or consider repeating these coop missions next level up.
[Tip] As with this and all co-op missions "spot" your enemies, this will help both off you in firefights where you are completly out-numbered, the name off the game is 'support' - 'survive - 'surprise' at every corner, room and building
Here's l ist off all available weapons' that you can unlock during your co-op missions.
MP412 REX: 63,000 points required. [all kits]
KH2002: 126,000 points required. [assault class]
MP7: 189,000 points required. [all kits]
M39 EMR: 252,000 points required. [recon class]
93R: 315,000 points required. [all kits]
SG553: 378,000 points required. [engineer class]
G3A3: 441,000 points required. [assault class]
[Note] When you reach a total off or exceding 445.000 you will earn the service star.