The solution is based on the US PC version of the game. There may be divergences from the Spanish version and / or for other platforms.
Watch the cutscene, waiting to wake up in bed. Once out of bed, locate the door on the left and use it to exit. Get rid of the children, talk to Rahim beyond the door.
Head to the side towards the flight of stairs, proceeding to the next area. Observe the cutscene, launching yourself towards the tube. Continue to the room where the noises are coming from, killing the zombie in the area. Move to the door, talking to the person in the area. You'll need to get some alcohol for him in the room on the left. Enter and retrieve the first aid kit, then return to the doctor, and then return to Rahim again. Change inside room 194, continuing towards the roof, reaching the top of the building and retrieving the crane. Climb to the top of the crane, then talk to Rahim, observing the cutscene.
Go down and follow the instructions that will follow, arriving at the elevator. Grab the ledge, then move the camera to face the next platform. Jump forward, until you reach the top. Climb up the crane, then watch the screen turn yellow. On the opposite side, talk to Rahim. Continue to the doctor, getting the Antinazine. Exit the tower, then talk to the doctor in the area. Then continue forward towards the caravan.
Talk to Zere, then to Spike to start the mission. Continue to the checkpoint, getting rid of the Biter in the area. Continuing further beyond the portal, kill the two Biter and open the nearby door. Kill the Runner in the area by activating the electricity near the wall.
After you call the GRE, get rid of the Biters around the two cars. Proceed to the checkpoint, where you need to activate a box. Kill the Biter, then look back and locate the Power Box with a pole associated with it: climb along the pole, then continue towards the power box. Continue towards the station, opening the garage door. Get rid of the person in the area. So kill the Biter and move beyond the red door.
Exit, so keep going forward to the bridge. Drop down and climb the pipes. Run along the pipes until you reach the stairs. Get rid of the Biter by reaching the safe zone. Use the nearby map to plan your route. Once in the safe area, go to sleep. After you wake up, contact GRE and then go talk to Brecken.
Video - International Press Citations
Exit, continue to the checkpoint, unlocking the secure area nearby. Continue north again. At the following checkpoint, locate the stairs leading to the Airdrop. Get rid of the Biters, watching the cutscene. So start running away to avoid crossing the oncoming birds. At the next "safe" area, make your way to the tower, thus arriving at the headquarters.
Pact with Rais
Make your way to the checkpoint. Once inside the area, observe the intermission scene. Talk to Kahrim. Listen to the instructions, talk to GRE. At the checkpoint again, get rid of the Runners in the area. Continue to the garage door, getting rid of the Zombie Acid. Go back to the garage door, opening it and getting rid of the two waiting Biter. Activate the switch, going up the antenna.
Now use the wire that goes down to the garage to quickly reach the next area. When you arrive at the station, you will notice how it is blocked by barbed wire. You will have to move beyond its top, locating the two subjects in the area. Climb on the antenna, then go back to Rais and then talk to Kahrim.
So go to Jaffar station. Talk to the man there to get the money back. Close the portal, freeing yourself from the biting area. Continue to the building going up to the second floor. Talk to Gursel, get the money back. Continue north, arriving at the port. Talk to get the money back. Taken all the money, continue to the Rais area. When you are halfway through, you will be contacted by Kahrim who will ask you to find the patrols. Continue towards the area indicated on the map, they will then shoot you from all sides. Run to the building in front of you, causing the propane tanks to explode. Collect the note in front of the building, getting rid of the Runners in the area. So go back to Kahrim, giving him the note. Go back to the tower, talk to Brecken.
Watch the cutscene, proceed to the right and pass the wall. Get rid of the Biter, continuing to the basement, and then go up to the roof. Locate the police van, then climb up to the sign until you reach the roof. Watch out for the Biter on the ground, get rid of them and also get rid of the zombies and Bombers in the area. Continuing to the door, make your way to the school.
Open everything you can to retrieve the items. Continue forward until you locate the first enemy, open the door activating the alarm. Still ahead, get rid of the enemies and biters in the area. Continue to the container, open it without unfortunately being able to find anything. Continue to the basement, retrieving the keys from the nearby drawer behind the table. Back in the basement, get rid of the Runners. Go down the stairs until you find the Biters in the corridor. Once in Jade, watch the cutscene. Get rid of the three enemies, then proceed and leave. Continue to the next "safe" area. Go back to the tower, talk to Rahim, then to Zere. Move to the safe area just south of Zere, then climb up the building in front of you, waiting for the right moment to take out the enemy. We recommend using a Speed Booster to maximize execution speed.
Talk to Rahim, then continue towards the overpass, kill the Biter near the bus, turn the body in front of you (Omar), then continue towards the trains, killing all the Biter near the car. Open the door. You have 3 minutes to place 2 bombs in the area before they explode and damage yourself. Then continue to the hive, talking to Rahims. Avoid the biters you will find nearby. Run up, going up to the hole in the floor. Turn left to reach the first play area. Some birds will arrive in the area: use the Flares to cause them to scatter. Then continue towards the stairs that allow you to proceed to the next floor, on the left.
Walk along the narrow path, placing the second bomb and proceeding to the dead end. Get rid of the muscular man. So move forward, still continuing towards the exit. After the explosion, go back to Rahim and watch the cutscene. Now go back to Brecken, tell him what happened. After the cutscene, get rid of Rais' men. Move towards Zere, then get rid of the subjects with guns.
Head to the Rais complex to retrieve Dr. Zere. Unfortunately, as soon as you arrive in the area, you will notice that it is not possible to proceed through the front area. You will therefore have to find another way to enter. Swerve to the right, locating the red pickup truck that crashed into the wall. You will then have to climb the scaffolding, reaching its top. At the top, jump to the right, locating three opponents in the area below. Kill them and proceed forward, also trying to locate the ropes in the vicinity. At the roof, you will find four more enemies, two on the right and two on the left - immediately take out the ones on the right, more dangerous than the others. Then locate the hatch, on the right area of the roof.
Use the elevator, then go down the shaft to proceed to the outside. Down the stairs, locate the subject on the left, eliminate him, then always continue forward locating the next enemy near the corridor. At the bottom, another enemy will come out of the doors immediately behind him. So check all the rooms to locate the items and pick them up. Move down, getting rid of two more enemies. When you reach the garage, locate the gun. Locate the room, then go down to the garage, proceeding to the building. Right, proceed upward, throwing yourself to the side as you clear the enemies. Make use of the propane cans, then head towards the van in the center. Turn right and hit the guns, then move forward again, arriving at the room with Zere in it.
After you wake up, you will notice how you have lost all your weapons and you will have to go and retrieve them as they are scattered throughout the arena. Watch out for the Biters and Runners. Jump over the containers and retrieve the Rebar, your strongest weapon. Jump across the container again, making the Runners catch up and hit them as they are running towards you. When there are only 2-3 biters left, go get the propane cans and throw them towards the center of the arena. Killed all the zombies, you will have to deal with the Demolisher. He is equipped with full body armor, which you will have to repeatedly attack to destroy. Only after the pieces of armor have been destroyed can you hit his "flesh". In these moments you will have to pay attention to his charge attack, to be dodged by moving towards one of the two sides. Always try to place the propane cans in the center of the playing area, so that the opponent goes to hit them during one of his charges.
With the Demolisher killed, watch the cutscene. You will therefore have to start running again, it will not be useful for you to continue fighting since the opponents will constantly shoot at you and you will not have the opportunity to "cover" yourself from their shots. Once you exit, you will begin to lose HP, continue forward avoiding the attacks of the Biter. Wait until you reach Brecken, watch the cutscene, retrieve your items and proceed forward to the next level.
Enter the roof, talk to the person near the door. Head to the tunnels. At the end, you will find your contact. Follow it until you reach the survivors. Wait for one of them to go and open the grate below. Swim to the opposite side. Once outside, go up to the left. Jump on the yellow pipe, move forward and jump forward again. Move along the tunnel. When you reach the crossroads, turn left and drop down to proceed further.
At the opening, get rid of the Biter. When you get to the fire, get rid of the Runners as well, as well as the big enemy nearby. Open the nearby hatch, then proceed forward and get rid of the groups of Biter and Runners. Move to the end of this area again, grabbing supplies and killing the Biter. Jump to the right, lunge forward, and drop into the water.
Stay in the water to avoid being hit towards you as you proceed towards the end of the stream. Equip your pistol now to take out the three subjects on the left and the two on the right. Proceed forward and swerve to the left. Proceed forward dodging the arrows to the exit. Once on the ground, locate the three enemies in the center, kill them and move towards the old city.
Find the Embers
Once out of the sewers, go talk to Jade. So try to talk to Troy who will tell you to go and meet her together with her Embers, inside the building called "Loft". Beware of the Zombies along the way, they will be very aggressive and have a greater amount of Runner-type "supporters". At the Loft, talk to Jade for additional information.
Proceed to the university, talking to the subject in the area and asking about Jade. She will tell you that she was previously in the area, only to have left. Exit the game area, Troy will then tell you to go and meet her near the Loft. With that done, head over to Michael.
Video - Launch Trailer
We recommend rushing to the sewers without paying attention to nearby enemies. So open the door and proceed towards the grate; swim under the grate, then return to the surface. Drop down and get rid of the Biter, then go up and move along the next tunnel. Open the door, then continue towards Michael, visible near the final area.
Collect all the bombs, go up the stairs, arriving at the first floor. Continue to the elevator, then go inside and move up to the fifth floor. Then continue to the ninth, locating the hole in the floor. Enter it and then continue to proceed up to the tenth floor. Get rid of the nearby Biters, then continue to room 105, where you will be "greeted" by two Biters. Place the bomb next to the stove, continue to room 106, ending the Zombie Acid in the area. So place the bomb. So talk to Michael, visible in the area. Go up the stairs to the twelfth floor, get rid of the three Runners and Biter's group. Enter the elevator hole, continuing to the thirteenth floor. Continue to the first room, getting rid of the Bombers in the area. Place the bomb, continuing to room 134, where you will hear a baby cry.
Move inside, the baby will start crying and you can leave the room, reaching the corpses. Kill the various Biter and place yourself behind the nearby doors. Killed all the zombies, go back to the previous room and kill the baby too. Place the bomb and proceed to the elevator. Grab the ropes and drop down the elevator shaft.
At the elevator, get rid of the various Biter, then re-descend and pay attention to the bomber on the right. At the exit, get rid of the enemy blocking the path, killing him quickly. So go out and watch the cutscene. Jade will contact you, head to the checkpoint and watch the cutscene.
Proceed to the checkpoint, locating the down stairs. So locate the tunnel as well, by swimming in its direction to reach your destination. Try to be quick while in the water, as if you can't reach the air zone, you will drown directly. Then locate the partially broken portal. Keep swimming straight up to the fence. Turn right, arriving at the dead end. Turn left, then retrieve the barrel floating in front of the hole.
At the checkpoint, swim up and climb to the top, locating the hole in the wall. Therefore, always continue forward. Head to the right, arriving at the portal. Observe the cutscene. Kill the three gun-toting subjects. Move to the next door, then make the gate move up. Wait for your stamina to increase again. Shoot, then move left. We now recommend avoiding the battle with the Biter: climb up from where you are now, then jump to the left. At the halfway point, destroy the guns that will shoot at you. So get rid of the small group of Biter, so you can proceed inside.
Look at the scene inside. Fight against the Biter in the area. After you kill them, watch the next cutscene. Follow Jade to the next room, moving through the door. When you get to the Zombies, watch yet another cutscene, then fight Tahir. After you damage him enough, kill the four guys he will try to bring to help. Get rid of the Biter in the area, running beyond them. Proceed to the exit, getting rid of the two guys in the area. Equip the items, then move towards Troy.
Once you reach the sewers, you will reach a barrier after a short run. Jump beyond it, thus continuing towards the child. Kill him quickly, thus calling the Runners in the area. Exit the room, letting the wall next to you fall apart and a breaker comes to the area. Avoid staying in this area - you would be forced to fight against an endless stream of Demolitionists, so keep going down to the rubbish on the right. Explore the buildings in the area, talk to Savvy to activate the station, recovering the Keycard to be able to enter without problems.
Move to the container closest to the fence, retrieving the Keycard with the Shotgun associated with it. Having taken the Keycard, move up the road, clearing the zombies along the way. Once at the station, get rid of the Biter. Move to the opposite side to enter, so get rid of the bombers. Now avoid entering the room used for activating the control unit, it is preferable to proceed towards the antenna, where you will find some biters waiting for you. Move to the generators, opening the panel on the left to activate them.
Now proceed towards the antenna, thus moving towards the elevator. Drop down, creating a shock wave. Get rid of the Runners, then proceed towards the center, moving up and looking left to locate a small group of ropes. Move forward, then climb up again, to the top. Get rid of the Biter in the area, then keep climbing up to the box. Observe the cutscene.
Now go down and talk to Volkan Dal. After the transmission, go back to the Tunnel. Move to the top of the stairs, getting rid of the Runners in the area as well as the nearby birds. At the next tunnel, start running again. To complete the objective, we recommend using the hook and "aiming" towards the ceiling, locating a series of cages. Project yourself towards the cages, but pay attention to the visible holes near the cage - if you reach a hole, you will immediately fall down. At the end of the route, you will notice the bus. Climb to the top, stopping the zombies trying to chase you. Move down to the old town.
Continue to the clinic, talking to Dr. Cadmen. Go inside and retrieve the guns at the top of the building. Get rid of the Biter and Runners in the area. Jump on the elevator, then go down to the laboratory.
Once out of the elevator, get rid of yet another Runner visible in front of you. Continue to the right, go up the shaft until you reach the security room. Get rid of the Biter at the bottom, unlock the doors and retrieve the Keycard nearby. Exit the room, then keep moving up to the corridor. There will be two other Biter in the area, as well as two others near the final area of the breaker beyond the portal. Then continue to the decontamination room on the left.
Go back to the office in the corridor. Wait for Cadmen to open the doors, then get rid of the Biter. Watch out for the bomber on the right. Proceed forward, then enter the conduit continuing to its end. Turn right to climb up the pipes, keep moving up the pipes to the corpse. Left to the next shaft, kill all the Biter, then get on the forklift to the right. Get the cranes down, then climb up and continue towards the conduit. Move along the pipes, then turn left to the next pipe. Get rid of the enemy in the room, use the forklift to pick up the crates and crouch under them.
Move to the generator room. Activate all the generators, then exit the room and get rid of the Biter. Use the Keycard to cause the portal to rise, then return to the decontamination room and press the switch to get rid of all the Biter in the area. Continue to Cadmen and watch the cutscene. Go back up and contact GRE.
Head back to the basement to deal with Rais. Move along the sewers, swimming backwards until you return to the surface. Get rid of the Biter in the area, move left until you reach the tunnel. At the path that proceeds outwards to the right, get rid of the Acid Zombies and the Biter. Continue to the end of the path, opening the trap door.
Quickly keep going up the stairs until you can't move forward. Open the door, observe the cutscene. Jump off the building, reaching the pile of garbage. Keep running to the next large area. Jump inside the manhole, then get rid of the child who will try to call the birds. Quickly run forward, equipping the flares, until you reach the ladder. At the top of the ladder, get rid of the Biter and continue to the green container in the center. Climb up, then up again to the top. Enter the elevator, waiting for the top floor to be reached. Get rid of the Biter, go up the stairs and talk to Kahrim.
Jump onto the crane, killing the Biter and Runner in the area. Wait for the Bomber to be in the area waiting for you. Kill the Runners, then the Biter. Go up the stairs and get rid of the other Biter. Exit to locate the wooden beams. Walk along the rafters, then jump forward and quickly kill the incoming Biter. Jump along the pillars, moving along the edges. On the opposite side, go up to the Bomber and quickly get rid of the Biter. Go up the elevator, then use the ladder to get to the top. Climb to the top of the crane, moving left. At the halfway point, quickly dodge the RPG shot that will be launched towards you. Launch towards the yellow sign, then continue to the top, move left, walking slowly forward. Turn right, go up the wall, then go up to see it directly with Rais.
The battle against the final boss will consist almost exclusively of skits in Quick Time. You just have to press the right buttons when they appear on the screen. Once this is done, you can enjoy the final scene without any problems!