Leon and Helena: Chapter 5
Follow the BSAA trooper and avoid the gas. Continue upstairs to the right and open the gate. After opening the gate, stay on the right side and immediately enter the building to avoid getting caught in the gas. After entering the building, you'll find another serpent emblem in one of the shelves there. You must shoot it and collect the items quickly as the glass window will break and the gas will seep inside.
Continue upstairs and destroy the crates along the way. Open the elevator and kill any zombies that will appear. Continue along the corridor and fend off a few more zombie waves then open the door. If you want, you can stick around this area for a bit to kill more zombies and earn more loot. Open the door and continue to the humvee outside. After reaching your destination, boost yourself up over the truck to reach the next area.
After meeting with Ada, head inside the alley and follow the familiar path until you crawl outside. Kill the zombies then check the open container truck behind the humvee to find another serpent emblem.
Continue to the next door and go along the narrow corridor. Don't run downstairs since there's a zombie horde that will rush towards you. Throw a grenade to save some ammo.
Head outside and follow the path until the same scene as the prelude triggers. Just do the same and run towards the helicopter.
After surviving the helicopter crash and before moving to the next door, look at the shelf to the right to find this emblem. Open the door afterward. Vault over the railing to continue to the next section of the chapter.
For this battle, you have to utilize the explosive barrels to significantly weaken this enemy. There are a lot of crates so don't hesitate firing at this enemy. Like before, get up close when he regresses back to human form and beat him up. Once he transforms back to his massive monster form, keep distance and try to lure him towards the explosive barrels. Keep shooting at him until the next sequence takes place.
Concentrate on firing at its eye while you're the gunner. After successfully repelling its attacks, you'll be back on foot. Just repeat the same process until he finally goes down.
After the scene, climb up the cable until you reach a ledge. From there, protect Ada by shooting off Simmons and some zombies from a distance.
Continue climbing up until you reach the window. As Helena, you should provide cover from the distance. As Leon, you have to stick with Ada and fight Simmons up close.
In the next area, Simmons will still show up. Keep distance and shoot him until he's weakened and the normal zombies swarm him.
Once inside the gate and before climbing the stairs, go under it and peek through the fence to find the last emblem of the chapter.
Continue upstairs and make your way to the helicopter. As you reach the crane, Leon will be knocked over the gondola. As Helena, make your way to the crane controls and activate it. Fend off against more enemies then reactivate the controls once it stops. Wait until Leon makes it through then open the gate together.
Continue moving on and vault over the railing to fight the large fly-monster. Aim for its legs to destroy it and force it grab any nearby zombie. Make sure to shoot the legs only when they're glowing. One of the zombies there as a lightning rod so clear all zombies in the area so the monster grabs it and gets damaged by the lightning. Keep shooting at its legs until it is weakened and falls down to the ground. Grab the lightning rod and run towards the monster to nail it.
After the battle, continue heading to the helipad until you reach the helicopter. Grab the rocket launcher and shoot the bastard in the face. Approach the helicopter again for another scene and to complete the campaign.