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Zero Protocol Walkthrough – Followchain

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Zero Protocol is an immersive sci-fi thriller in the IAS Antarctic Research Complex.

Inspired by classic 3D games like Half-Life, the game offers a non-linear storyline.

Solve puzzles, repair equipment, and search for access cards while navigating a cold atmosphere.

With multiple endings, every decision shapes your fate as you balance clarity and madness.

This article contains a Zero Protocol walkthrough guide on how to solve all codes, puzzles, and grids for levels 1 to 8.

Zero Protocol Walkthrough

LEVEL 1 [Medical Center]

First room: 1685

Where to find it: On the computer in the same room

Intensive Care 2 (right outside the first room): 542768

The hint: One of the two terminals inside the room opposite Doctor B. Wayne’s Office, option 1 (ICU 2, password).
Where to find: Room opposite of Doctor B. Wayne’s Office on a piece of notepad paper next to the terminal. Combine with the hydrogen peroxide in the Research Department (Room 1.1) to see the password.

Doctor B. Wayne’s Office: 2001

The hint: Paper on the bench right outside the first room (Intensive Care Unit 1)
Where to find: Poster seen through the window in the room with the save point. If facing the save point, strafe right slightly and go straight—that window.

Admin S. Sobolev’s Office: 128418

The hint: One of the two terminals inside the room opposite Doctor B. Wayne’s Office, option 2 (strange symbols).
Where to find it: Right outside the room on the wall. Sanity needs to be <60%

Security Office: 950318

Where to find: Wall inside the same office. Go around the other side of the checkpoint and look through the window.

EPS room (power room) (needs to be opened via the terminal in Room opposite Doctor B. Wayne’s Office (option 3, door control: EPS): 257 is the pager code. Check the note in the room with the grid puzzle, right above the controls.

X 0 X
0 X X
0 0 X

The hint: Terminal inside Intensive Care Unit 2, option 1 (get_to_pager)
Where to find: Kill the zombie after opening the security door via the terminal. The pager is on his dead body. Look at it.

Storage room: 5242

Where to find: Paper on crates right past the Security door and the first wire you have to jump over.

LEVEL 2 [Storages/Security]

Turret: HX 222 DN 023

To get here: You can either use the key found in the bathroom on the floor somewhere or just shoot the lock.
Where to find: Storage. Note on the right shelf. Notice that the #7 turret is missing.

Security (upon returning back): 12451

Where to find: Shower room inside barracks (Sleeping Quarters) on the poster.

C.S.O. R. Brooks Office: 3110

The hint: Note inside barracks (sleeping quarters). “I wouldn’t be surprised if the code was his son’s birthday” Please note the code is based on the European date format (DD/MM).
Where to find: Admin D. Su’s Office right next door on the terminal. Option 1, A Personal Request. See date (10/30 USA, 30/10 EU). It says his son’s birthday is tomorrow (10/31 USA, 31/10 EU. Code is 3110)

Storage 2: 55555

Where to find: Piece of paper right next to the door. Your sanity must be higher than 90% to read it. Once inside, shoot the lock off. You don’t need a key.

LEVEL 3 [Labs/Greenhouse]

Laboratory A (first passworded door with big A next to it): 28006

Where to find it: On the window next to the door. It’s backward.

LEVEL 4 [Vents]

Nil.

LEVEL 5 [Residential Floor]

Kitchen/Canteen (room 3): 144126

The hint: Terminal in Admin V. Verner’s Office, option 1, The password has been changed
Where to find: Dormitory room 4. Note in the room.

Locked Door in Kitchen: 112263

The hint: Note next to door
Where to find: Dormitory room 3. Book on the bed.

Security Post Card Bypass Terminal (see map once you find it), (see below if you want to try and solve it yourself + explanation):

The Answer: 388 968 625 898

How to solve:

Hint 1: Underscores mean nothing. Don’t try to put a number in them. Don’t overthink this like I did.

Hint 2: On the bottom set of numbers: You have to start with one of the 5 sets of numbers in the first column on the left.

Hint 3: Pretend the top set of numbers is just one giant number (with a few underscores here and there). It’s nothing more than a coincidence that there are 5 rows on both the top and bottom sets of numbers.

The Explanation: Easier than it looks. You just need to find the first working sequence of numbers you see on the bottom, from left to right, top to bottom, on the top set of numbers. You’ll notice a couple of 388’s in the second row on the top set of numbers. The first one right after a blank (or an underscore) shows the correct number sequence. Simply input it.

Admin M Verner Grid:

X 0 X 0 0
X 0 0 X X
0 X X 0 X
X X 0 X 0
0 X X 0 X

The hint: A floor plan you pick up of a dead body shows possible locations (via question marks) of various items. 2 of these are noted for the grid. They are random.

LEVEL 6 [Life Support Floor]

Generator Room: 4221

Where to find: The map on the wall in the Power Engineering room shows the code

Storage: 4412

Where to find: The map on the wall in the Power Engineering room shows the code

Restroom: 121017

Where to find: SE section of Generator room. Note on the floor. Requires high sanity to see

Workshop: 13

The hint: Security Post terminal, option 1 (Once again about passwords!). “I set the simplest one, two digits. Just download the FLOOR PLAN and look at it.”
Where to find it: On the map once you get it. Press M

Main Engineer: 515253

Where to find: Walls opposite the door. Requires low sanity (<50%)

Air Purification Grid Puzzle:

East Side

X X 0
0 X X
0 X 0

West Side

0 X 0
X 0 X
0 X X

How to solve: In the same room, you’ll find a chart that shows what to input into the computers. If you step outside and look above the windows for the opposing locked door (the one you’re trying to open), you’ll see two numbers. 1 and 8. Go back to the chart and input the grid code for 1 and 8.

LEVEL 7-1 [Server Floor] (If you took the vent instead of the elevator)

Admin R. Villar’s Office: 14001

Where to find: Room 6: Отдел анализа данных (Data Analysis Department). You can get in this room by killing a zombie somewhere on this floor and swiping their keycard

Control Terminal 1:

X 0 X
X X X
X X X

Where to find: Note in Room 6: Отдел анализа данных (Data Analysis Department)

Control Terminal 2: USE the Master Keycard r##### on the door lock. Then just rearrange top to bottom, left to right, the number at the top

Inside the room:

X 0 X
X 0 X
X 0 X

Security post (Room 5): 65412

Where to find: Room 6: Отдел анализа данных (Data Analysis Department). You can get in this room by killing a zombie somewhere on this floor and swiping their keycard

Storage Room (Room 4): 306208

Where to find: On the walls outside the Security Post (room 5). Requires low sanity.

LEVEL 7-2 [Laboratory 44] (If you took the elevator instead of the vent)

No map. No Names. Pick a door. It’s one of those: 1340

Where to find it: Look through the window of the security office. It’s on a note.

Jail Grid C2:

X 0 X
X 0 0
0 X X

Where to find: CS D. Baraev’s Office on a terminal, option 1 (Updated key table)

Jail/Isolation Area:

Room A: Already open, but, 900635

Room B: 021403

Room C: 248887

Where to find: Two random notes are scattered on this floor. Find them. Combine them. Read them. I found mine in lab 1 after killing a zombie and the security office maybe.

The door across from Storage: 021197

Where to find: Appears above the door after talking to the shadow in laboratory 1 through the window in there. I also had high sanity.

Storage: 213412

Where to find: Appears on walls in the same hallway as Storage with <50% sanity

New Pass Grid 5×5:

0 X X 0 X
0 0 X X X
X X 0 X 0
0 0 X X X
0 X X X 0

Where to find: Appears on the wall near the room after activating the scanner and merging minds with Victor Altman. I had <50% sanity but that may not make a difference.

LEVEL 8-1 [Administrative Floor] (If you took the vent instead of the elevator on Level 6)

Across from V. Altman’s Office: 200705

Where to find: Given from Talking Supercomputer

V. Altman’s Office: 000004

Where to find: Given from the person inside the room across from this one (oh wow, big spoiler!)

LEVEL 8-2 (If you took the elevator instead of the vent on Level 6)

Follow the directions given by Victor Altman

The 6 triangle things are solved by going around the corners to the walls near them and matching the symbols that I would have a hard time re-creating here. Can’t miss it. Easy peasy. Walk across the bridge and enjoy the ending.

Further reading

Five Hearts Under One Roof Guide

Felvidek Walkthrough

Workplace Fantasy Walkthrough