I did a small guide to show all the spots where there are special people to talk to. There is 32 of them in total so not every level in the game will have special person. Some of them can be find within first 5 seconds while others are hidden.
Also small spoilers ahead.
Level 1-3 – None
For the first three levels, there isn’t any special people to talk to.
Level 4 – Metro Station
After first fight when going upstairs, there is one person to the right. You can talk to them but be careful, because they disappear once you go to the left and start combat.
Level 5 – Restroom
Hiding inside the toilet cabin in upper-right corner. It will be possible to talk to them once you finish whole combat.
Level 6 – Abandoned Metro
It’s on the very beginning of the level, in front of machines.
Level 7 – Train Tunnel
It’s on the left side of the map, kneeling next to a wall. You need to finish whole combat so you can talk with them.
Level 8 – Sewers
Another one that is on the beginning of the level, hard to miss. Right before the first door, there are small stairs on the right that can take you to that person.
Level 9 – Shipyard
After the whole crane section, there is a person sitting on the container that you need to go through to proceed. All you need to do is stand in front of container and you will be able to talk with them.
Level 10 – The S.S. Muggler
This one is actually hidden. When there is a section where you need to take stairs three times to go on the top of the ship, before going through third stairs you need to go down and then to the left. There will be one person kneeling down behind boxes.
Level 11 – Oil Rig
On the second half of the level, there is a person that is looking through the window. After the combat, you can spoke to them.
Level 12 – None
It’s a jet ski chase, hard to find a person to talk to on the open waters.
Level 13 – Civilian Evacuation Center
Another one that is a bit hidden. Before the end of the level, there is a combat inside the building with torture chairs in it. Instead of going up like the game tells you to, you can go to the right on the small bridge to find a person there sitting and fishing.
Level 14 – Gas Station
After talking to a guy hidden inside the closet, in the middle of the gas station a person will appear, stealing items from shelfs.
Level 15 – Motel
Right before the level ends, after the combat on the pool you can go to down-right corner of the pool to find a person there sitting.
Level 16 – Hawthorne Diner
It’s on the start of the level right after you enter the diner. After finishing combat inside the room, you can spoke to that person.
Level 17 – Game Studio
After the pillow fight on the last floor, a room in down-left corner of the floor will get unlocked. You can go inside and talk with Eric Jacobus there.
Level 18 – Train Station
On the beginning of the level, instead of going inside the train station, you can go to the right and talk with a person there.
Level 19 – Slums
On the beginning of the level, before the first combat you can see a person just standing in front of the building. Hard to miss.