“Welcome to ZERO PROTOCOL, where codes, puzzles, and grids await! This guide is here to provide hints and nudges for solving puzzles, but also includes spoiler-marked answers for when you’re truly stuck. Endings are also achievable with the help of this guide, but don’t worry – no details will be revealed. Keep an eye out for secret notes that can only be read at certain levels of sanity and remember, you can shoot off padlocks. X’s on grids indicate what to fill in and I’ll do my best to describe rooms and objects without giving away puzzle solutions. Let’s get to it!”
LEVEL 1 [Medical Center]
Where to find: On the computer in the same room
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The hint: One of the two terminals inside room opposite of 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 terminal. Combine with the hydrogen peroxide in the Research Department (Room 1.1) to see password.
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The hint: Paper on bench right outside first room (Intensive Care Unit 1)
Where to find: Poster seen through window in room with the save point. If facing the save point, strafe right slightly and go straight. That window.
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The hint: One of the two terminals inside room opposite of Doctor B. Wayne’s Office, option 2 (strange symbols).
Where to find: Room opposite of Doctor B. Wayne’s Office.
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Where to find: Wall inside same office. Go around the other side of the checkpoint and look through window.
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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 zombie after opening the security door via the terminal. Pager is on his dead body. Look at it.
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Where to find: Paper on crates right past Security door and first wire you have to jump over.
LEVEL 2 [Storages/Security]
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 right shelf. Notice that #7 turret is missing.
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Where to find: Shower room inside barracks (Sleeping Quarters) on the poster.
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The hint: Note inside barracks (sleeping quarters). “I wouldnt be surprised if the code was his son’s birthday” Please note the code is based on the European date format (DD/MM). Check
Where to find: Admin D. Su’s Office right next door on 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)
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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]
Where to find: On the window next to the door. It’s backwards.
LEVEL 4 [Vents]
NONE
LEVEL 5 [Residential Floor]
The hint: Terminal in Admin V. Verner’s Office, option 1, The password has been changed
Where to find: Dormitory room 4. Note in room.
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The hint: Note next to door
Where to find: Dormitory room 3. Book on bed.
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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.
I’m really bad at explaining things, but here goes:
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 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.
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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 off a dead body shows possible locations (via question marks) of various items. 2 of these are notes for the grid. They are random.
LEVEL 6 [Life Support Floor]
Where to find: Map on wall in Power Engineering room shows the code
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Where to find: Map on wall in Power Engineering room shows the code
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Where to find: SE section of Generator room. Note on the floor. Requires high sanity to see
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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: On the map once you get it. Press M
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Where to find: Walls opposite the door. Requires low sanity (<50%)
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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)
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
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X 0 X
X X X
X X X
Where to find: Note in Room 6: Отдел анализа данных (Data Analysis Department)
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Inside the room:
X 0 X
X 0 X
X 0 X
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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
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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)
Where to find: Look through window of security office. It’s on a note.
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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)
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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.
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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.
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Where to find: Appears on walls in same hallway as Storage with <50% sanity
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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 wall near 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)
Where to find: Given from Talking Supercomputer
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Where to find: Given from the person inside the room across from this one (oh wow, big spoiler!)
LEVEL 8-2 [The Monolith] (If you took the elevator instead of the vent on Level 6)
Follow 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.
And that wraps up our share on ZERO PROTOCOL: Codes, Puzzles, and Grids [Spoiler free or tagged]. If you have any additional insights or tips to contribute, don’t hesitate to drop a comment below. For a more in-depth read, you can refer to the original article here by Dogiboi, who deserves all the credit. Happy gaming!