Head down the path and turn left near the bridge. You'll find a small piece of metal sticking out from either edges of the gap. Head towards it and press space to jump across.
Once you get to the other side, turn right and you'll find one of the bridges support beams. Stand in front of it and jump to get on the metal bars that form a ladder.
Climb up and around the support beams until you get to the part where a railing is attached. Keep going until you pass the rails and press space to climb up and regain your stamina.
Walk along the beam until you can't proceed anymore. When that happens, press the right mouse button (RMB) and shimmy along the side of the beam. You'll find another ladder at the right side of it.
Proceed down the path and you'll find a small metal beam sticking out from under the bridge. Get on it and jump towards the one in front of you.
Climb up the beam then turn right. You'll see a larger beam support structure on that side, stand in front of it then press jump and make your way up the ladder.
You'll find a gap in the ladder. Press space to jump it, this will burn a lot of your stamina. Now quickly continue up the ladder and press space after getting on the last one. Recover your stamina then drop down the side of the beam and onto the ladders at the left side.
Climb up the beams and keep going to the left. Once you're on the second ladder, you'll have to go all the way to the right and up the third ladder.
You'll most likely run out of stamina before you can even reach the top. Spam the left mouse button (LMB) until you get to the top.
Now press C and you'll see your inventory. Let's talk about items for a bit. When you burn your stamina it won't go back to full like it used to. The only way to get it back is through drinking water. Sodas on the other hand only replenishes your stamina, but doesn't return the burned stamina.
Keep going to the right and you'll find a metal rope on the side of the platform. Stand in front of it then jump, slide down and drop down on the bridge.
Go left and you'll find another part of the bridge sticking out towards a metal cage. Jump towards it and keep moving forward until you get to the end, then climb up.
Continue down the bridge and you'll find a firetruck at the right side. Climb down on the lowered part of the bridge and hang on the side until you get to the ladder on the firetruck.
Climb down the ladder and drop down on the support beams below it. Now use the upper part of the support beams and make your way to the other side.
Keep going to the other side of the bridge and you'l find another large gap. Slide down on the left side and use the remaining support beams to climb across.
Enter the sewers and turn right at the first crossing. At the end of that path you'll find the entrance to the sewers on the left side. Go in to proceed.
Proceed down the sewer line and a man will call your attention.Don't approach him and don't pull your gun on him. Just walk away and he'll leave you alone.
Now turn right and climb up the fallen parts of the floor to get on the streets.
When you're out on the streets, turn left and keep following that road until you see the garbage truck, then turn right on the alley beside it.
Climb on top of the boxes and use them as leverage to reach the top of the mesh gate. Now drop down on the other end and head for the gate on the right side.
As you approach the gate a guy with a machete will call out to you. This guy is hostile, so even without any bullets pull out your gun. Press space to make him back up on the hole.
Approach him but don't take too long trying to scare him. Some of these guys will realize you have no bullets and attack you. When you're close enough, press E to drop him down the hole.
With the machete in hand head back to the gate and press E to start prying the lock open. Spam the LMB to destroy the lock and exit the area.
You'll then be harassed by additional thugs. Wait for the one with a gun to approach you, then press E to surprise kill him. Now point your gun at the second guy and scare him. That guy will surrender to you so you don't have to kill him at the moment.
Turn right and two more thugs will come at you from the side. Wait for them to approach you and shoot one of them, then point your empty gun at the second one and approach him. Press E to do a struggle kill (spam LMB to win).
You can then approach the guy who surrendered and press E to knock him out. Never leave any of them alive or conscious. You never know what will come to bite you later.
Make your way to the right side of the street and get around the blockage, then proceed to the other side and use your machete to open the gate.
Drop down on the collapsed part of the street and pick-up the first aid kit on the center of it, then climb back up through the left side.
Follow the street until you get to the police barricade, then turn right into the alley where you'll find a mother and her wounded son. These are survivors, you can choose to help them if you have the necessary item to do so and you'll get an extra retry for doing so. Just keep in mind that resources are limited and you're practically giving them your life support.
Exit the alley and turn left. Keep going down the street and an old lady will shout at you. Don't be jumpy, she won't shoot you. Just pass through and she'll leave you alone.
Continue down the street and turn left, you'll find a light post that was used as a makeshift bridge across the gap. Use the beam and make it to the other side.
Head down the street and turn left at the first intersection. Keep walking and a cutscene will play, then head inside the apartment.
Inside the apartment head for the fireplace and you'll find a letter written by your wife. After reading it leave the apartment.