In the main menu, choose Campaign > New Game > Veteran. It is far more efficient to have your first playthrough be on Veteran difficulty so you can grab all of the collectibles and miscellaneous achievements in one playthrough. However, if some miscellaneous achievements / collectibles end up being too difficult for you to complete on Veteran difficulty, you can always mop them up on an easier difficulty via chapter select after you complete the main story.
While I found Ghosts' veteran campaign to be easier than previous Call of Duty games, you'll find it is still a very challenging difficulty. Here are some tips before you begin:
- Take cover as much as possible, and proceed slowly. If you're out in the open, even just one enemy can tear you apart and send you back to your last checkpoint.
- Take advantage of the auto-aim system in this game by quickly snapping to an enemy with , shoot, and repeat with other enemies.
- Your squadmates in this game are much more helpful than in previous Call of Duty campaigns, and they'll even provide you with helpful callouts (i.e., follow and listen to your squadmates).
- If you feel like you've hit a wall and simply can't proceed, take a break. Seriously. There are a few sections that can cause excruciating frustration. When this happens, it's best to just put the controller down, take a break, and come back refreshed.
Mission 1: Ghost Stories
The prologue consists of an introduction to the Ghost's, the main characters (Elias, Hesh, and Logan) and an overview of the 'mass event' that occurs at a space station, and on Earth.
Objective: Return to ODIN control
Once you're in the flashback in space, your station will be hijacked by enemies. The game will naturally provide you with a gun during this section, and once you kill an enemy, you'll unlock:
Once the space section ends, you'll be back in the present with Hesh. As you sprint forward and avoid the destruction, keep to the right side and you'll quickly come upon a house that has a car parked in the driveway. Vault over the car, enter the already opened door to the house, and laying on the floor is Rorke File 1/18.
Continue to follow Hesh. Upon completing the mission, you'll unlock:
Escape. (Complete "Ghost Stories" on any difficulty.)
Mission 2: Brave New World
Objective: Backup Team at LA River Checkpoint
Once you've fought through the sewer section and reach the end (green smoke with friendlies), you'll be told to pick up a launcher that's laying on a crate (the "MAAWS). Holding aims a laser that directs the shot of your rocket after firing with . Shortly after you pick up the launcher, 2 attack choppers will fly in. Your goal is to take out both of the choppers using the launcher. The first attack chopper flies in low and will go away if you're not quick enough to take it out (if this happens, simply reload your checkpoint). Once you've destroyed the first chopper, do the same thing with the second chopper flying above. Once you've taken out both choppers, you'll unlock:
Take down both attack helicopters in Brave New World.
Objective: Report to Elias with Hesh
Once you've reunited with Elias, follow him upstairs with Hesh, and sitting on the table just before the balcony is Rorke File 2/18. Follow Elias and Hesh out on to the balcony, and the mission will end. Upon completing the mission, you'll unlock:
Brave New World
Rendez-vous in Fort Santa Monica. (Complete "Brave New World" on any difficulty.)
Mission 3: No Man's Land
Objective: Gather Intel on Federation Activity in the Area; Meet Up with Recon Team
Early on in the mission, you will be in control of Riley (the dog) to sneak up on and attack enemies. There will be two different instances where you play as Riley in this mission. For your next achievement, you need to kill a total of 10 enemies as Riley. This is quite easy to complete as long as you're patient and avoid getting spotted. The first time you play as Riley, there are a total of 4 enemies to kill. Once you've killed the fourth enemy, you will automatically progress in the mission. Later on in the mission, when you play as Riley again, there will be more than enough enemies for you to kill the 6 left for your achievement. To avoid getting spotted, make sure you stay in the tall grass as much as possible, and try and predict enemy movements. Once you've gotten your 10th kill as Riley, you'll unlock:
Shortly after your first time being in control of Riley, you will come across an old construction site that has a lot of debris. At the end of this site, you'll see a metal building (it's the only building in this area). Inside of the building, on the middle table, is Rorke File 3/18.
Upon completing the mission, you'll unlock:
No Man's Land
Make it to San Diego. (Complete "No Man's Land" on any difficulty.)
Mission 4: Struck Down
During this mission, you will be in control of a remote sniper a total of 4 times. While you're in control of the remote sniper, you need to make sure you do not miss a single shot for an achievement. Some people have reported that when they've missed a shot, they reloaded their checkpoint, continued on with the mission, and earned the achievement. However, this doesn't seem to be the case for everyone. You can certainly try and reload your checkpoint and try again if you do miss a shot. However, if it doesn't work for you, then simply skip this achievement for now and play it on an easier difficulty via chapter select later.
Objective: Rescue Ajax
Once you ambush the convoy and drive up into the stadium, you need to clear the entire upper balcony and progress forward until you'll be given control of the remote sniper for the first time. During this sequence, you just need to kill 1 or 2 enemies, then your teammates will do the rest (remember, you can't miss a shot!).
Shortly after this, you will be in control of the sniper again. This time, there are a total of 4 RPG-wielding enemies you need to kill before you can proceed with the mission.
Later on in the mission, you'll breach another door. Once it's breached and the enemies are dead, go to the left side from where you entered, and resting inside of a locker is Rorke File 4/18.
Objective: Escape From the Enemy Base
Shortly after collecting the Rorke file, you'll enter your third remote sniper segment. This one is the trickiest, because there are a lot of enemies for you to kill, and they move around a lot. Simply take your time and make sure you will hit your shot before you fire. Once it's clear, head to the chopper, and you'll soon enter your fourth and final sniper segment. This one is fairly easy, since all you need to do is shoot the gunners that are on top of the vehicles. For not missing a single shot with the remote sniper for the entire mission, you'll unlock:
Every shot with the remote sniper kills a person or vehicle.
Once you've flown away in the chopper, you've reached the end of the mission. Upon completing the mission, you'll unlock:
Find Ajax. (Complete "Struck Down" on any difficulty.)
Mission 5: Homecoming
Objective: Get to the Front Lines
At the very beginning of the mission, follow your squad through the camp until you enter a small house. Before heading up the stairs in front of you, go left to the small room, where sitting on a table is Rorke File 5/18.
Objective: Defend the Beach from the Federation Invasion
As you're defending the attack, you'll eventually be given the option of calling in A-10 attack drones at several different points. Make sure you use these attacks whenever they're available, along with ensuring the drone strike is aimed at a large group of enemies. The attack itself is very powerful, and you shouldn't have any problem killing a total of 50 enemies during the mission. Although you're supposed to use the drone strikes to take out choppers and tanks, you can simply use the attack to take out large groups of infantry as well. Once you've killed a total of 50 enemies with the drone strikes, you'll unlock:
Upon completing the mission, you'll unlock:
Defend LA. (Complete "Homecoming" on any difficulty.)
Mission 6: Legends Never Die
Objective: Get to Higher Ground; Locate Almagro
Early on in the mission, you will fail your objective, and the city will flood. Once you reach the roof, it will collapse, then you'll be swept by the flood and left with only your knife. Rorke will tell you to sneak up on an enemy and take him out with your knife. When you do this, make sure you are crouched underwater as you press the melee button, since you need to work on killing a total of 6 enemies with your knife while you're underwater. Although this is possible to complete on Veteran, this might be one that you want to mop-up later on an easier difficulty if you're struggling.
Just after you get the first underwater knife kill, you'll follow Rorke up to the high ground, where you'll then have to cross a long, moving platform to get to the building on the other side. Once you've made it to the building, there will be two enemies in the first room to kill. Once they're taken care of, head to the computer desk behind them and grab Rorke File 6/18.
Objective: Regroup with Merrick
Shortly after grabbing the Rorke file, you'll come up to some enemy sections where some enemies are above water on high ground, while others are in the water. This is where you need to continue killing enemies with your knife while you are crouched underwater. Enemies will still see you when you're crouched underwater, so you can't really take a "stealthy" approach here. However, just try your best to maneuver through the water to get close to enemies, then quickly crouch and kill them with your knife. Again, if you find this to be too difficult (you likely will), then you can mop this up later on an easier difficulty. However, once you do manage to kill 6 enemies with your knife while you're crouched underwater, you'll unlock:
It Came from Below!
Kill 6 enemies with the knife while underwater in "Legends Never Die".
Continue through the underwater sections and follow your objectives. Once you complete the mission, you'll unlock:
Legends Never Die
Hunt down Almagro. (Complete "Legends Never Die" on any difficulty.)
Mission 7: Federation Day
Objective: Capture the HVT
Play through the opening scenes until you cut open the window and enter the building. Once inside, go around the left-hand side wall and enter the first room on your left. In the back right corner of this room, on one of the desks, you'll find Rorke File 7/18.
Objective: Upload Virus to the Power System
Shortly after gathering the Rorke file, you'll be tasked with uploading the virus. Once that's done, you'll hook back up to your rappel. Once you're on the rappel again, look down and to the left for a balcony with two enemies on it. Take them out, then descend two more floors down and look inside of the window to find an enemy sleeping on a chair. Shoot him to unlock:
Here is a video guide in case you'd like a visual of where the sleeping enemy is:
Continue the rappel section, then you'll end up back inside of the building. During these sections, you'll go through several rooms of enemies to kill. Continue onwards until you disable the elevators and hook up to the ropes. While you're rappeling on the ropes, an explosion will occur above you and debris will start flying out. One of these pieces of debris is a large, white photocopy machine. Simply let the machine hit you as it's falling (it may or may not kill you), and you'll unlock:
Once you finish the rappel section, you'll enter the building one last time. Simply follow your objectives to complete the mission, and you'll unlock:
Gather intel on Rorke. (Complete "Federation Day" on any difficulty.)
Mission 8: Birds of Prey
At the beginning of this mission, you'll be in control of an Apache helicopter. The helicopter has lock-on missiles as well as a machine gun for you to use.
Objective: Assault Factory
Use a combination of your lock-on missiles as well as your machine gun to take out the targets marked on your screen. As you are flying around, you'll notice that there are a bunch of fuel canisters in nearly every building. As you are flying around, check every rooftop, house, and bridge for fuel canisters. When you see one, shoot it so that it explodes. You need to destroy a total of 80 fuel canisters, which might seem like a lot, but they're everywhere. Here's a visual guide for you, just in case there's some hidden away in areas you may have missed. Once you've destroyed 80 fuel canisters, you'll unlock:
Objective: Find Rorke
Once the helicopter section ends, you'll be on the ground with your squad. Keep progressing forward, taking out enemies along the way, and you'll eventually end up back in the Apache helicopter again. Once that's done, you'll be back on the ground. Continue forward, and you'll end up in a room with Rorke himself. While your teammate deals with Rorke, quickly head to the desk in the middle of the room that he was leaning on for Rorke File 8/18.
Shortly after grabbing the Rorke file, the mission will end, unlocking:
Birds of Prey
Capture Rorke (Complete "Birds of Prey" on any difficulty.)
Mission 9: The Hunted
During this mission, you will end up alone in enemy territory. For an achievement, you need to make it through the entire mission without being spotted. In general, you need to be patient in predicting enemy movements. Furthermore, you should not engage any enemies unless you are told to do so, or if you absolutely need to in order to avoid being spotted. If you are spotted, you can quickly reload your last checkpoint and try again.
Objective: Regroup with Ghosts
Once you're in the jungle, you need to meet up with your squad without getting spotted. This isn't very difficult to accomplish, as long as you take it slow and are constantly looking at your heartbeat sensor for enemies. Remember, I recommend you don't engage with enemies unless it's absolutely necessary to proceed. At your first checkpoint, you'll come upon some burning rubble. To get through this area, stick to the left side and proceed forward in a clockwise-motion, using the natural cover when necessary. At the end of this area, there will be a waterfall on the left-hand side (this is where you regroup with the Ghosts). Before proceeding forward, look on the left side rocks just before the waterfall to find Rorke File 9/18.
Objective: Evac to the River for Exfill
Now that you've regrouped with the Ghosts, you need to complete the remainder of the mission without being spotted. This is fairly easy to accomplish now that you're with your squad again, since they will tell you what to do in most sections. After you get through the river section, you'll be in another forest. Again, just stick with your squad and proceed slowly in order to avoid detection. Once you're through the forest, you'll be in some tall grass while enemies are heading in your direction. To avoid being spotted here, simply stay directly behind one of the Ghosts and keep crouched the entire time.
Once you've made it through the tall grass, Hesh will say, "Holy shit. Is that nuclear?" -- when this happens, you need to sprint ahead to the rocks in front of you, then immediately go prone in the tall grass just prior to them, because a chopper will quickly appear on your position. If you're not quick enough going prone in the tall grass, you will be spotted.
Once the chopper passes, you're home free. Simply follow your squad to the exfill, where you'll complete the mission and unlock:
Finish the mission without breaking stealth.
4 guides The Hunted
Make it out alive (Complete "The Hunted" on any difficulty.)
Mission 10: Clockwork
Objective: Get Into Base Undetected
Once you and your squad drive into the base and the power goes out, you'll be told to use your night vision goggles to kill the enemies. Once the enemies by the gate are taken care of, head up the stairs and into the room on your right that's labeled "Sector 2". Inside of this room, sitting on the table with a computer is Rorke File 10/18.
Continue playing the mission and you'll get to a section where you have to defend a room while a file downloads. During this section, make use of all your equipment (i.e., mines, turrets) along with your tactical and lethal grenades. I found it best to stay in the equipment room for a while, then gradually move out to the catwalks as more enemies spawn in at different areas in the room. Once you hold off the attack while the download completes, you'll exit the facility.
Objective: Get to the Extraction Point
As you're escaping the facility in a vehicle, you will take control of a grenade launcher turret while enemy vehicles are chasing you. With this turret, you'll be going for an achievement to make a total of 8 vehicles fall into ice holes. In order to create an ice hole, you simply need to aim the grenade launcher a bit in front of one of the vehicles chasing you and shoot the ice. Once you've shot a hole open in the ice, the enemy vehicle will fall into the hole once it drives over it. Note that not every vehicle will actually "fall" into the hole, and they'll sometimes just hit the hole and spin out -- this counts as them "falling" into the hole. Once you've destroyed a total of 8 vehicles via the ice holes, you'll unlock:
Shortly after earning the aforementioned achievement, the mission will end, unlocking:
Hack the system (Complete "Clockwork" on any difficulty.)
Mission 11: Atlas Falls
As you play through the first half of the mission, make sure you do not use any of your flashbangs or grenades. Both of these are essential for an achievement you'll be going for about halfway through the mission (while on Veteran difficulty).
Although you won't be using lethal or tactical grenades for the first half of the mission, don't worry -- there aren't a ton of enemies, and your squadmates are very helpful in the beginning sections.
Objective: Fight to the Pressure Regulators
Once you've ascended using the grapple gun, you'll have to clear out a few rooms of enemies. Once you've moved up to deck two, Hesh will use tape to blow open a door, then you'll head upstairs. At the end of this area, a quick cinematic will occur where you'll breach a door and Merrick will throw you down so you avoid the gunfire. Once the door is opened, do not enter it -- this room is known as the "common room", and you need to clear it without taking any damage while on Veteran. This is easier than it sounds, as long as you've hung on to your flashbangs and grenades.
To start, simply edge your way to the doorway and toss in a couple of flashbangs, followed by some frag grenades. Be very careful with how far you peek into the room, as you can take damage almost instantly if you're too exposed. Once you've exhausted all of your frags and flashbangs, then slowly sweep the room with your guns. It's worth noting that Merrick and Hesh can also be helpful in taking out some enemies, so just take this section slow. You'll know the room is clear once you've earned a checkpoint. Speaking of which, if you do get hurt, you can simply restart your checkpoint and try again. Once all of the enemies are dead, and you never took any damage, you'll unlock:
Piece of cake
Storm the common room and kill everyone without taking damage on Veteran.
Once you've cleared the common room, you'll go through another door into a control room, where Merrick deals with the foreman. Before you interact with the controls, enter the small room on the right side, and grab Rorke File 11/18.
Objective: Take out the Enemies on MG's
Later on in the mission, after you've taken out the enemy MG's, you'll head up some stairs and will be told to maintain the water pressure while Merrick overloads the pumps. This is done by interacting with the console to remove the dead body, then you'll be in control of the water pressure valves. All you need to do is move and and try to keep the three bars in the middle, such that they are colored green. If they move into the yellow for a bit, that's okay, as long as you quickly adjust them so they're green again. If it turns red, you'll fail and will need to reload the checkpoint or the entire mission and try again. Once all of the pumps have been blown up, and you kept the pressure bars from entering the red zone, you'll unlock:
Blow the pressure valves on your first attempt.
Once that's done, all that's left is to follow your squad and escape the oil rig, completing the mission and unlocking:
Distract the Federation Fleet. (Complete "Atlas Falls" on any difficulty.)
Mission 12: Into the Deep
Objective: Neutralize the AEGIS Class Combat Ship
A little bit into the mission, after swimming through the cave and cutting open a door, you'll swim up through a lighthouse. At the top of the lighthouse, Keegan will tell you to launch the Proteus missile. Luckily, you don't need to worry about lining up your aim perfectly, because you get to control the missile once you launch. Once in control of the missile, control its movement with and aim for the direct middle of the ship that is glowing red, orange, and purple. Once you've landed a perfect hit, the ship will be destroyed, and you'll unlock:
Objective: Regroup at the Rally Point
After you've recovered from the destruction of the ship, continue to follow Keegan. Eventually, you'll swim through some of the destruction of the ship, and some enemies will appear in front of you (Keegan will say "More divers! Take 'em out!"). At this point, look at the rock slightly ahead of you and to your right for Rorke File 12/18.
After you get through the section where you swim past the sharks, you've reached the end of the mission, where you'll unlock:
Into the Deep
Destroy the enemy ship (Complete "Into The Deep" on any difficulty.)
Mission 13: End of the Line
In the very beginning of the mission, you will be given a prompt to drop down and kill an enemy with your knife. This is the first out of five silent kills you need to obtain at the beginning of this mission. The remaining 4 silent kills need to be done by you, and not your teammates. If you do end up getting spotted, you can simply reload the entire mission and try again. Here is a visual guide you can follow along with:
Objective: Infiltrate the Factory
After your first silent kill, proceed forward and slide out of the forest into the train yard. On your left side, just near the first set of train tracks, there will be a single enemy patrolling. You can either take him out with a well-placed headshot, or sneak up behind him and melee him for your second stealthy kill.
Next, continue to follow your teammates towards the building on the left. You will come to an area where there are 3 enemies ahead of you, and your teammate will tell you to take the shot. Headshot any one of these enemies, and your teammates will clear up the rest, giving you your third stealthy kill.
Just after that, your teammate will open up the garage door in front of you. As the door opens, go prone and quickly take out the next 2 enemies that will appear right in front of you. Since these are your last 2 enemies to take out, you can spray your suppressed weapon to quickly take them out without being noticed. Once they're dead, and you've successfully killed all 5 enemies in a row without being spotted, you'll unlock:
Cog in the machine
Kill 5 enemies without being detected before infiltrating Black Zone.
From here on out, you don't need to worry about playing the mission in stealth, although you might find it to be easier. Continue on until you open up a pressurized door and enter a large missile room.
Objective: Upload Visual Scans of the Weaponized Rods
As soon as you enter the missile room, before you take pictures of the missiles, run down the stairs and immediately turn around. Sitting on a box in front of you is Rorke File 13/18.
Continue to play through the mission, and once you reach the end, you'll unlock:
End of the Line
Storm the factory (Complete "End of the Line" on any difficulty.)
Mission 14: Sin City
The beginning of this mission includes several minutes of unskippable cutscenes. Simply follow the button prompts on screen until you're in control of Logan again and given the objective to "escape".
Pick whatever weapons you'd like, then continue to take out enemies with Hesh, Keegan, and Merrick. You will eventually come to a set of stairs that lead down to a large, Egyptian-styled casino (on your left will be "The Pharaoh's Club", and on your right will be the "Bar Lounge"). This room will be loaded with enemies, so take your time killing them all.
Once this area is clear enough for you to proceed, continue forward to the next set of stairs. At the bottom of these stairs, there will be more enemies, along with a bunch of slot machines. After you've cleared out all of the enemies in this section, begin shooting the screens of all 20 slot machines. After they're all destroyed, follow your teammates to the next room by sliding under the gate that Keegan is holding open for you. Immediately after this, look to your left to find Rorke File 14/18 sitting on a table in a rest area.
Continue forward, and you'll very quickly come upon another escalator. Before going down, look across the room to the far balcony, which contains more slot machines. Again, destroy the screens of the slot machines, and you will unlock:
All that's left now is to escape, completing the mission and unlocking:
Plan your next move. (Complete "Sin City" on any difficulty.)
Mission 15: All or Nothing
Objective: Get to the Flight Deck
Immediately at the start of the mission, once in control of Logan, turn around and head slightly forward towards the bunks on your left. Resting inside of the bottom bunk is Rorke File 15/18. Once you've collected it, head to the Flight Deck and prepare to take out the enemies.
Objective: Regroup with Hesh
Once you've cleared the flight deck, go to your objective (Hesh), and you will be told to interact with the Osprey controls. Once that's done, immediately run ahead to the side of the ship where enemies are spawning in. Once the enemies are close enough to the ship, they will throw grappling hooks up to the deck. Once this happens, head to one of the ropes and wait until you see an enemy rappeling up. As they're rappeling, you will be given a prompt on the grappling hook to press the melee button to cut it. Once you've cut the rope that had an enemy on it, you'll unlock:
Continue to defend the carrier for a few minutes, and once you've successfully defended the enemy attack, you'll complete the mission and unlock:
All or nothing
Gather the troops. (Complete "All or Nothing" on any difficulty.)
Mission 16: Severed Ties
Objective: Rendevous with Bravo Company
The beginning of this mission will have you controlling a tank. Once you're in control of the tank, continue following your squad forward to the area full of ground satellites. As you're taking out enemy tanks here, you'll quickly get a prompt on your screen that says "press to switch weapons" - do so, such that you're equipped with guided rounds. Once the enemy helicopters come in, fire your guided missile at a helicopter and control it in air to destroy the helicopter. You don't necessarily need to directly impact the helicopters with the rocket, and you can actually just press to manually detonate the rocket mid-air. As long as the rocket is near the helicopter when you detonate it, the helicopter will be destroyed. Once you've destroyed 3 helicopters in a row with the guided missiles, you'll unlock:
Take out 3 out of 3 helicopters with the remote missile.
After you've finished the tank section, you'll fly in on a chopper and take out enemies inside until you've secured the launch room, at which point you'll be told to launch the missile.
Objective: Reach the Train
After launching the missile, head down the stairs with Hesh, and he will kick the door open. Once it's opened, head into the corridor on your immediate right, then go into the first room on your left. Inside of this room, sitting on a terminal, is Rorke File 16/18.
Continue to fight with Hesh until you reach the train. After that, you'll be back in control of the tank for the remainder of the mission, tasked with destroying the turrets along with enemy soldiers, tanks, and choppers. Upon completing the mission, you'll unlock:
Destroy the Federation's satellite array. (Complete "Severed Ties" on any difficulty.)
Mission 17: Loki
Objective: Assault the Station
This mission puts you back into space. Simply take your time killing the enemies here, then make your way towards the open hatch, which will trigger an explosion. Once you're back in control, head a bit forward and take out the two enemies in front of you. Once they're taken care of, quickly look to your left for a shiny, orange piece of debris. Floating just to the left of this piece of debris is Rorke File 17/18.
Once you've breached the control room, interact with the console, and you'll be in control of the rods.
Once you're in control of the rods, you'll be going for one of the more difficult achievements in the game. You'll be in control of the rods and can use
to fire up to 3 rods at a time at the ground enemies. Once you've fired a sequence of 3 rods, you can immediately fire more rods again. Your goal is to eliminate all of the enemies (excluding helicopters) with the rods, but without killing any of your allies. If you think you've accidentally killed an ally (you won't always get a message on your radio stating you've killed an ally), immediately restart your checkpoint. You should pause your game and look at the video below to see how it's done.
Objective: Eliminate the Incoming Federation Forces
Once you're in control of the rods, your screen will light up with a ton of enemies. Simply use as many rods () as you need to clear them all, as there aren't any allies around this part. After this, your allies will light up on your screen as well as the enemies, so you need to now carefully position your rod shots such that they kill all of the enemies without harming any of your allies. Remember to quickly reload your checkpoint if you do end up killing one of your allies. Check the video below if you'd like a visual guide to see how this is properly executed. Once you've destroyed all enemies with the rods, without killing any of your allies, you'll unlock:
After the rod section ends, you've completed the mission and will unlock:
Commandeer the enemy space station. (Complete "Loki" on any difficulty.)
Mission 18: The Ghost Killer
Objective: Find Rorke
Right when the mission starts, turn around and look in the corner of the room for a red tool cabinet where you'll find Rorke File 18/18, your final Rorke File for:
Follow Hesh as you progress through the train, taking out enemies along the way.
Objective: Take Out the Enemy Helo's
Once you've progressed far enough in the train, enemy choppers will fly in for you to destroy. Simply stay in cover (don't proceed too far ahead) and shoot the gunners, then the pilots, to quickly destroy the choppers. Once they're destroyed, continue forward and be on the lookout for enemies that are rappeling in on the sides of the train. You need to shoot and kill 2 of these rappeling enemies before they reach the top of the train, although there are a total of 4 enemies rappeling in. If you aren't quick enough in killing 2 of the rappelling enemies before they reach the top, you can quickly reload your checkpoint and try again to successfully unlock:
Shoot the grapple guys off the side of the train.
The rest of this mission is very linear and mostly cinematic. Once you've completed the mission, along with the entire campaign (on Veteran), you'll unlock:
Miscellaneous Achievement: Safeguard
There is one "multiplayer" achievement in the game, although you can complete it entirely solo and offline. However, it is strongly recommended you do this with other people, as some of the later waves can prove to be quite challenging in solo. Your goal is to reach wave 20 in "Safeguard", which is a survival-based game mode.
In safeguard, you and your teammates will start out with a pistol and face waves of increasingly difficult enemies to kill. As the rounds progress, the game will drop in weapons, perks, and killstreaks for you to collect. Furthermore, some waves you'll be given a field order to complete (i.e., get 10 headshots, 10 knife kills, etc.), which, when successfully completed, will provide you with more powerful weapons and killstreaks.
In the main menu, go to Squads > Safeguard (not Safeguard Extended) and choose if you want to play solo or cooperatively. Pick any map you want, then survive until wave 20. If you're struggling to reach round 20, here is a nice method by YouTube user "TheZombieProject" that shows you how to easily reach round 20 on the map "Warhawk":
Once the game ends after you've completed 20 waves, you'll unlock: