Solving the first chapter puzzles in Backrooms Lost Dimension requires finding four key items—the Red Lever, three Film Reels, and the Maintenance Key—by deciphering environmental clues in Office Zone 4B. This guide provides the exact, step-by-step solutions for every puzzle you'll encounter before reaching the elevators to Chapter 2.
Chapter 1, titled "An Unscheduled Orientation," serves as a tense introduction to the game's logic. The entity known as The Static Man is less aggressive here than in later levels, but its presence means you cannot afford to linger. The puzzles are primarily observational, rewarding players who meticulously check their surroundings.
How to Open the Office Zone 4B Keypad Door
The very first obstacle is a locked metal door with a 4-digit keypad, blocking access from the initial yellow lobby into the main office maze. The code is randomized on every playthrough, but the method for finding it is always the same. The four required digits are scattered around the starting room, hidden in plain sight.
Finding the Four Digits
The numbers are etched into the environment, often revealed by flickering lights or subtle details. You must find all four before the keypad will accept the input. Their locations are fixed:
- First Digit: Look at the large, buzzing fluorescent light fixture above the overturned water cooler. As it flickers, a number will be briefly visible on the metal casing. This is always the first digit of the code.
- Second Digit: In the corner to the right of the locked door is a small, potted plant that has withered. Inspect the base of the pot; the second digit is engraved on its terracotta surface.
- Third Digit: Find the employee desk with a non-functional CRT monitor. Look underneath the desk, near the right leg. The third digit is scratched into the wood, as if by a key.
- Fourth Digit: On the wall opposite the keypad door, there's a patch of damp, peeling wallpaper. Interacting with it will peel back a corner, revealing the final digit written in black marker on the wall behind it.
Backrooms Lost Dimension in-game screenshot
Entering the Code and What to Expect
Once you have all four digits, approach the keypad. Enter them in the order you found them: Light Fixture, Plant Pot, Desk Leg, Wallpaper. Upon successful entry, you'll hear a heavy clunk, and the door will swing open. Be prepared to move immediately. The sound often attracts The Static Man, so do not dawdle in the doorway. Proceed directly into the cubicle maze ahead.
Navigating the Mannequin Storage Maze
Beyond the keypad door lies a dimly lit storage area filled with dozens of faceless mannequins. This is not a traditional maze with a single solution, but a stealth and observation challenge. Your goal is to find a Red Lever on one of the mannequins to restore power to the next section.
How the Mannequins Move
The mannequins are harmless but unsettling. They follow a simple rule: they only move when they are not in your direct line of sight. When you turn your back, they will subtly change their poses or shift their positions. This is meant to disorient you and can be ignored, with one exception: a single mannequin will move to block your path if you take too long, forcing you to find an alternate route through the shelving units.
The key is to ignore their movement and focus on the task. Systematically check each mannequin's hands. Most are empty, but one holds the critical item you need.
Locating the Red Lever
The Red Lever is always held in the left hand of a single, specific mannequin. This mannequin is distinguished from the others in three ways:
- It is the only one wearing a single black glove on its right hand.
- It is positioned directly under a flickering emergency light.
- It never changes its pose, unlike the others.
The location of this specific mannequin shifts between three possible spawn points within the storage room. Sweep the room methodically, keeping an eye out for the glint of the emergency light. Once you find it, grab the Red Lever. You will hear a distant hum as partial power is restored somewhere in the level. You can now leave the mannequin room the way you came in; the path will be clear.
The Screening Room Projector Sequence
After using the Red Lever on a clearly marked power box, you'll gain access to a small corporate screening room containing a 16mm film projector aimed at a blank screen. The projector is missing its reels. To proceed, you must find three Film Reels hidden throughout the office area and place them on the projector in the correct narrative order.
Backrooms Lost Dimension in-game screenshot
Location of Film Reel 1: The Birthday Party
This reel is the easiest to find. Head to the breakroom area, identifiable by the vending machines and stained couches. On a small round table, next to a collection of moldy coffee mugs, sits the first film canister. The label is faded but reads "J.S. - B-Day '92".
Location of Film Reel 2: The Office Meeting
Return to the main cubicle maze. Look for a corner office with a smashed window (the only one in the area). Inside, on the floor amidst the scattered papers and glass, is the second film canister. Its label reads "Q3 Financials - URGENT". This is the reel depicting the office meeting.
Location of Film Reel 3: The Empty Park
This is the most well-hidden reel. Find the executive washroom area. Inside the last stall, the toilet tank's ceramic lid is slightly ajar. Interact with it to lift the lid, revealing the final film reel submerged in the clean tank water. The label is water-damaged but you can make out the word "Park".
The Correct Reel Order and the Revealed Clue
Return to the screening room with all three reels. You must place them on the projector in chronological order to tell a story. The correct sequence is:
- The Birthday Party ('92)
- The Office Meeting (Q3 Financials)
- The Empty Park
Placing them in the wrong order will cause the projector to jam, forcing you to restart the sequence. When placed correctly, the projector will whir to life and play a short, silent film. The film shows a man celebrating his birthday, then working late in an office, and finally sitting alone on a park bench. At the very end, the film cuts to a close-up of three wall clocks in an office, each showing a different time. The screen will freeze on this image. Memorize the three times shown on the clocks. This is the combination for the final puzzle.
Cracking the Manager's Office Safe
The image from the projector is the key to the safe located in the locked Manager's Office. The door to this office is now unlocked after the film plays. Inside, you'll find a large, imposing portrait and a small, rotary safe built into the wall beneath it.
Finding the Combination from the Wall Clocks
The safe combination corresponds to the times shown on the three clocks in the film. The film always shows the same three times, which form a three-number combination for the safe: 4 - 8 - 15.
To enter the code on the rotary safe, follow the standard procedure:
- Turn the dial clockwise (right) at least two full rotations, stopping at 4.
- Turn the dial counter-clockwise (left), passing 4 once, and stopping at 8.
- Turn the dial clockwise (right) directly to 15.
The safe will click open. There is no threat in this room, so you can take your time.
Backrooms Lost Dimension in-game screenshot
What's Inside: The Maintenance Key
The only item inside the safe is a single, brass key on a plastic tag. The tag reads: "MAINTENANCE - LVL 2 ACCESS". This is the Maintenance Key, the final item needed to complete Chapter 1. Grab it and exit the Manager's Office.
The Final Door and Chapter 1's "True" Ending
With the Maintenance Key in hand, you can now exit the level. The exit is a heavy, red door marked "Stairs / Elevator Access" at the far end of the main office floor.
Requirements for the Standard Ending
Simply use the Maintenance Key on the red door. It will unlock, and you can proceed into a stairwell. Walking down the stairs triggers a cutscene and loads Chapter 2. This is the standard completion path.
How to Unlock the Secret "Janitor's Closet" Ending
For the chapter's secret ending and its associated achievement, do not use the key on the red door. Instead, backtrack to the area just past the Mannequin Storage room. There is a small, unmarked janitor's closet here that was previously locked. The Maintenance Key also unlocks this door.
Inside, you will find a mop bucket and a note. Reading the note triggers an alternate cutscene where the level geometry begins to corrupt and break apart, leading to a unique, non-standard game over that sheds more light on the lore of the Lost Dimension. This also unlocks the "Breach Protocol" achievement.
Chapter 1 Puzzle FAQ
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What happens if The Static Man catches you? In Chapter 1, The Static Man is slow. If it catches you, the screen will fill with visual static and you will be returned to the last puzzle checkpoint—for example, the entrance to the Mannequin room or the Screening room.
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Can I miss any items and get stuck? No, the level is designed linearly. You cannot access the next puzzle area without solving the previous one and collecting the required item (Lever, Reels, Key). All items are mandatory to progress.
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How long does Chapter 1 take to complete? On a first playthrough, Chapter 1 typically takes between 30 to 45 minutes, depending on how quickly you solve the observational puzzles. A speedrun can be completed in under 10 minutes.
A Masterclass in Environmental Storytelling
Chapter 1 of Backrooms Lost Dimension sets the tone for the entire game. It teaches you to look closer, to listen carefully, and to understand that the environment itself is both the lock and the key. By forcing you to piece together a fragmented narrative through film reels and hidden numbers, it does more than just gate your progress; it builds a world of quiet desperation that makes the eventual appearance of its hostile entities all the more terrifying.